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    "source_key": "britannica_1926",
    "source_title": "Encyclopaedia Britannica (1926)",
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    "chunk_id": "1926:agriculture:c4f907195213",
    "title": "AGRICULTURE",
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    "verified_text": "this article is divided into four main sections: j. a general sketch of the progress of agri- culture from rg1o; it. an account of the scientific developments; iii. the economics of agriculture, discussed under the three headings of credit, insurance and prices; iv. the use of electric power for agricultural operations. i. general survey the last quarter of the 19th century witnessed an unprece- dented fall in the prices of all agricultural produce, especially of wheat and meat. this was due to the opening up of new areas, particularly in america; in the united states alone 300,000,000 acres of land were brought under cultivation between 1870 and 1900, an area greater than that which was being farmed in europe during the same period. it was great britain with its open markets, with its great em- porium trade, with its increasing population already far out of proportion to the productive capacity of its land, that experi- enced the full brunt of the competition; other european coun- tries protected their farmers by tariffs; one country alone—den- mark—seized the opportunity to expand her agriculture. to the danish farmer, educated and adaptable, cheap corn and feeding stuffs afforded a means of producing butter, bacon and eggs for the ever-growing english market, and of making a profit on the conversion. the opportunity was equally open to the british farmer, but he did not display the same adaptability in taking advantage of it. with industries near at hand com- peting for men and capital, the english farmers and their men were not prepared to give the high level of ability and labour for the possible returns that contented the danish small farmers; morcover, the latter had worked out a system of co-operative marketing which for the first time enabled the agricultural com- munity to hold its own in international commerce. the growth of agricultural co-operation in the last quarter of the 19th century may be regarded as the other great discovery of that epoch, which will rank with fertilisers and machinery in recasting the agriculture of the future. prices —despite the inroads the farmers of america and of the other new countries were making upon the welfare of euro- pean agriculture, it cannot be said that this period of expansion was one of particular prosperity for them. they lived and mul- tiplied exceedingly, but it has been stated that in the aggregate the only profit they made came from the rising values of their land as the community grew round them. on the whole wheat and the other staple crops were being sold at below the cost of al production measured in terms of labour, which is the only ulti- mate standard. the later period down to the outbreak of war in 1914 saw a gradual rise of prices and the restoration of mild prosperity to british farmers, though any general confidence in the future of agriculture was slow of growth. they had modified their meth- ods to meet the conditions, they were paying more attention to education and scientific developments, they were adapting them- selves to the special market at their doors and though all too large a proportion were contenting themselves with an unen- lightened routine of cutting expenditure to the bone so as to take a profit out of what the land itself would give, the ever difh- cult situation was being met. then followed the world war with a few years of exalted prices and undreamt of profits for all farmers with a well-ordered business. the reaction was equally sudden, and the pit into which agriculture fell was deeper than the peak to which it had temporarily ascended. the war had caused a great stimulus to wheat production, in particular in the americas (22,000,000 ac. in the united states, 13,000,000 ac. in canada, 2,000,000 ac. in south america). markets began to be temporarily overstocked, and if the great break in prices in 1921 was mainly financial in origin, to the farmer it was accen- tuated by an existing surplus. moreover, the war had forced up wages to double or treble their former level, to one more nearly comparable to that pre- vailing in the industries, while the standard of work rendered had fallen. if to these causes we add a succession of bad seasons from 1921 to 1925, seasons that would have hit the arable farmer hard under the most normal of price conditions, it is small wonder that british agriculture is still staggering under the blow and doubtful which way to take for safety. american farmers have been little less severely hit. in the agriculture yearbook for 1923 it is reported that in 15 corn and wheat producing states in 1922 8-5° of owner farmers lost their farms with or without legal proceedings, and the percentage of tenants who lost their prop- er:y ran materially higher. the bankruptcy cases among farmcrs rose 10 14% of the total as compared with about 5%, which was the figure for pre-war years. but american agriculture is chiefly suffering from the dispar- ity of reward that it offers as compared with the industries; no single-handed farmer working even a well-established 160-ac. farm can hope for the cash returns that a bricklayer can earn, after all allowance has been made for board and lodging. prices of agricultural produce are high as judged by old standards, but the farmers’ outgoings have risen in a much greater proportion. particularly where there is a surplus of production above home requirements, a surplus that has to be sold in european markets, the price at home is forced down by competition to a parity with this european level, one which is below the average cost of production. tn european countries, where as a rule peasant farming and protection tariffs prevail, the agricultural community is com- paratively speaking prosperous; the farmers’ expenditure on raw materials or equipment is small, he and his family supply the labour, so that he reaps almost the full advantage of the higher prices and the depreciated currencies. live stock —two types of livestock production exist: grazing on ranges of natural pasture, and more intensive production under artificial feeding. as regards cattle the two systems inter- mingle; the cattle may be raised on the pastures and sold thence to other districts for finishing. for example, much of the beef produced in great britain begins as store cattle raised in the west or north or imported from ireland or canada, and then fattened on the rich pastures of the midlands or the coast, or in the yards of the arable farmers. similarly feeder cattle from the ranges 1n the united states travel to the middle west in ordcr to be fattened. the tendency throughout the world is for ranging to be ex- changed for cultivation, consequently the number of range cattle tends to diminish, and this tendency is not compensated for by corresponding increase in cattle raised on the mixed farming that succeeds the ranging. milch cattle always then begin to 52 grow at the expense of beef cattle. in australasia an increase in cattle production is still possible, chiefly in queensland, but there is no great unstocked area available as there was 50 years ago. south africa is still an undeveloped country as far as the international meat trade goes; a few live cattle are being exported to great britain for slaughter, but ranging in south africa is subject to much greater risks from disease than in america or australasia. so far, no freezing works have been put up to develop a trade, and until this is done and communications are improved, the capabilities of south africa and of the highlands of central africa to add to the beef supply of the world will remain obscure. beef.—nor is it quite clear to what extent the demand for beef from european countries will persist, stimulated as it has been by the supplies poured in from america in 1918 and 1919. prior to the war, european countries other than great britain were not great consumers of beef but rather of pork and dairy products, their agriculture being founded upon milk and pork production. when cheap grazing is not available the production of beef requires a larger consumption of food than that of pork; in consequence the agriculture of arable countries like germany tends toward the more economical production of milk and veal, or of pork. the beef consumed is cow or ox beef rather than that of steers or heifers deliberately fattened for the purpose; in fact the purely beef breeds of cattle are little known in europe. thus beef is somewhat of a luxury article of consumption com- pared with pork. if the dietaries of germany and the united states before the war are compared, with an equal supply of energy the american obtained 39-6% from animal foods, of which 5-3 °% was beef, whereas the german obtained only 32-4% from animal products, of which 3:2% was provided by beef. thus the supply of beef in the world may be expected to decline with the diminution of range conditions, while the price must rise to meet the more expensive methods of production. sheep.—specially marked, however, has been the reduction in the number of sheep that took place during the war and since. the following table shows a comparison for some of the chief sheep-producing countries between 1913 and the most recent year for which statistics are available. sheep per- centage change 1924 (or latest available) 017 17,000 15,460,000 +12 10,172,000 — 37 22,239,000 — 8 38,300,000 — 26 36,209,000 —i16 14,514,000 —45 31,224,000 —i3 80,110,000 6 23,776,000 tots 4,987,000 +15 16,441,000 16,176,000 24,279,000 51,482,000 43,225,000 26,286,000 35,808 ,000 85,057,000 24,182,000 germany spain . france . great britain united states of america argentina uruguay. union of south africa australia new zealand 327,923,000 | 280,721,000 the reduction has been in part due to encroachment on the pastures for cultivation when corn prices were so high, and in australasia to the lack of a market when transport was no longer available. great britain lost 4,542,000 sheep between 1914 and 1920, a loss which has only been repaired since to the extent of 3,350,000. the decline in britain took place in great measure in those districts where arable sheep farming prevailed, where the sheep are kept for the greater part of the year in folds on turnips and green crops. during the war the arable land was wanted for corn, and both then and since the heavy labour costs incurred both in growing the green crops and in working the folding have made this form of intensive sheep farming unprofit- able. it is only in england that this form of sheep raising is general; in all other countries sheep are grazing animals generally reserved for the poorer and drier lands. for this reason sheep farming does not bulk large in the farming of any other euro- pean country, except in spain where there are great tracts of poor and mountain pasture, not utilisable otherwise. sheep in- agriculture deed rarely play any considerable part in peasant farming on cultivated land, even under the most intensive system of folding upon green crops. the finest wool is that provided by the merino sheep, which originated in spain but had become widely diffused toward the close of the 18th century. it was with these sheep that the new countries—south africa, south america, australia, new zea- iund—were at first populated, because wool was the only product exportable, but since the introduction of refrigerated transport they have to some extent given place to lincolns, romney marsh, leicesters and some of the short-woolled breeds because of their better carcasses. for the really dry countries with rain- falls of 10 in. and less merinos still hold their own, though a new race, the corricdales, evolved from crosses between merino and lincoln, is coming into favour. on land suitable for cultivation sheep will always give place to more intensive forms of farming, but nothing can well take their place in the hill country, especially where the rainfall is low. their numbers are not, therefore, likely to grow in the more settled countries, and there does not as yet appear to be any area available for ranching unless it be some of the high land of central africa. pigs—lf{ sheep are associated with the pastoralist and the open spaces, pigs are presumably the live stock of the arable farmer, and are especially valuable to the dairy farmer turning his milk into butter or cheese. pigs are the great converters of the maize of the middle western states into a more salable form of produce, and the bacon industry of denmark has been built up on the by-products of the dairy and cheaply purchased cereals. danish farmers have indeed given a lesson to the whole world in the skill with which they have standardised the pro- duction of a type of pig suited to the bacon trade. american pigs are in the main of the wrong conformation for bacon, and run too readily to fat, especially upon the predominating feeding with maize; english pigkeepers are perplexed by an unnecessary multiplication of breeds, often with conflicting ideals. the value of the danish breeding has lain in the elimination of all other considerations than the requirements of the bacon factory. the great exporting countries of pig products are therefore the united states and t5 an increasing extent the argentine, and, in europe, denmark, holland and sweden. the higher-priced danish and sweclish bacon goes chiefly to great britain, which with germany takes also large quantities of the considerable american produce. population and foop supply at the present time live stock production is the most profit- able side of farming. there is still abundant grazing land to produce meat cheaply with a minimum of labour, and cereals are still relatively cheap for the dairy-farmer and pig-feeder, whose business consists of converting these materials into milk and meat. if food supplies begin to grow short the scarcity will first be felt with regard to meat, indeed many observers consider that a definite shortage of meat supplics is already within sight. with a diminishing herd of cattle and sheep flock the time is not far off when the united states will be a competitor for the meat output of argentina and new zealand instead of the largest exporter of meat and animal products. everything, therefore, points to rising prices for meat, so that increased attention to live stock production is likely to be the most profitable line of business for the british farmer. as civ- hisation proceeds and the populations grow, meat will become more and more a luxury, because the open grazings on which alone cheap meat production is possible will become settled. moreover, a community that is outgrowing its food supplies must become more and more vegetarian. as scarcity approaches, the land must be given up increasingly to the production of direct human food. that day is of course remote, but the indi- cations would point to a gradual tightening of meat supplies and therefore in a country like britain, accustomed to a high stand- ard of living, to increasing opportunities to the farmer who spe- cialises in live stock production. agriculture the growth of population during the 19th century, unprece- dented in the world’s history, was rendered possible by the open- ing up of new lands of america, north and south, of australia, new zealand and south africa. if we exclude from considera- tion the east (india, china, japan), where the available land was already utilised to the full and the density of population was already excessive, excluding also tropical countries, we find that the area of land cultivated for the white peoples expanded from about 440,000,000 ac. to over 880,000,000 acres. now upon the present basis of agriculture something more than two acres of land has to be cultivated in order to maintain one unit of popu- lation, man, woman or child, the amount being lower for inten- sively cultivated countries like holland, denmark or belgium, or great britain. of course maintenance includes other neces- sary agricultural produce besides food. for example a portion of the cultivated area is given up to fibre crops; and wool and hides are by-products of the livestock industry. other instances could casily be given. areas still for cultivation —working upon this basis alone that about two acres of cultivated land are necessary for the maintenance of one person, it is evident that in the tempcrate regions of the world there is no longer land available for the feeding of any large increase of the present population. in europe there are still great areas of forest, swamp and heath that might be brought into cultivation, but the process would involve an expenditure both of initial capital and continuing labour out of proportion to the returns. lither the prices to be received for produce must rise greatly, or the cultivators must be content with a lower standard of remuneration, before there is much addition to the european area under cultivation. in fact the present tendency is in the other direction; only italy with its great pressure of population increase is adding to its farming land and reclaiming wastes. all over the poorer jand of great britain abandoned holdings and crofts may be traced, abandoned for eco- nomic reasons alone, because men would no longer live and work so near to the starvation level. nothing but the direst need or a new scale of prices whereby agriculture becomes relatively the most paying industry will ever bring such land back into cultivation. other european countries to a less degree show the same tendency at work. in the united states there are still great areas of potential farm- ing land; for example o. c. baker (economie geography, 1925) esti- mates a possible increase of the wheat area in the united states of america from the present 80,000to 130,000 square miles. but little of this, however, is the natural easily farmed land the settler looks for; the efforts to make good the arid lands by dry farming and irriga- tion show that the good land has mostly been taken up. what remains is land on which capital outlay is required, jand on which production will always be more costly than on the great fertile plains of the middle west. asin great britain, the recent tendency in the united states has been to abandon the cultivation of some of the poorer lands and let them fall back to grazing. canada still presents enormous potentialities for settlement, though the vast areas the map reveals are severely restricted by increasing aridity toward the west and by cold northwards; baker considers an increase of the wheat area from 25,000 to 120,000 sq. m. as physically possible. but similarly on most of this land the wheat will have to be more dearly bought, by labour, fertilisers and skill, than on the land now being farmed. the potentialities of south amcrica are less easy of estimite, but in this region there is still a great area of rich plain country un- settled, and it is not too much to expect that another 40,000,000 ac. of land are available for farming under present conditions. the potentialities of non-tropical africa and of australia are small; in the latter country the arid zone lics so near to the coast that the additional area available for normal cultivation is negligible in considering the world’s need of food. the great unknown factor in this survey is western siberia, a natural wheat area, and man- churia. all that can be said is that the physical possibilities are great, perhaps as high as 300,000,000 ac., but no one can guess whien that wiil be realisable, dependent as it is upon the establishment of a stable and ordered government. moreover, on the tlank of these regions hang the vast unsatisfied populations of china and japan, ever ready to expand as the means of sustenance permit, and on this account the expectation of food from this area for the western peoples can be but small. the data are too approximate for an exact estimate, but it is at least clear that the good land still available for settlement in the temperate regions of the world will never permit of an expansion of population such as took place in the i9th century and indeed is inadequate to meet the present rate of increase. as potential sources of food there still remain the tropical coun- tries, in particular brazil and central africa, where abundant rain- falls and high temperatures render feasible a very high level of pro- duction from the soil. the last 50 years have witnessed remarkable examples of organised production of tropical crops under western direction and management. the growth of sugar in java, cuba and hawaii, of rubber in ceylon and the straits, of tea in ceylon and o3 assam, afford examples of the possibilities of organised agriculture, employing the resources of science, the labour-saving power of machinery, the criticism of cost book-keeping, such as can rarely be paralleled in the farming proper of the temperate regions, the same organisation is being extended to the coconut, which, converted into margarine, is becoming one of the chief edible fats of the worlc. without doubt the tropics present enormous potentialities of food production for the world, mainly in the direction of oil seeds and edible beans. it must, however, long remain uncertain to what extent the cheap native labour upon which these tropical exploita- tions are dependent will continue to be available. it does not appear to be possible to maintain a white population itself engaged in the cultivation of the soil in contact and competition with native labour, and queensland is the only tropical country where agricultural development is being attempted with white labour only. in this brief survey it is only possible to indicate the broad grounds for supposing that the food production of the world as at present organised is on the point of becoming inadequate for the demands of the growing population. the enormous growth of the roth century was rendered possible in part by the dis- covery of fertilisers, but in the main by the opening up of the new lands, particularly in the united states and canada. the united states is already beginning to call for imports, and will soon require all the food she produces and no longer have an exportable margin for over-populated europe. under a system that calls for two cultivated acres to support a unit of population there is not sufficient jand in sight capable of settlement to provide for much further growth of population. the continual rise of foo<l prices since the beginning of the cen- tury—and it would appear that the trend is being resumed after the violent fluctuations caused by the war—is further evidence that the process is at work. the process is being accentuated by the growing disinclina- tion of the civilised peoples to engage in agriculture, because of its small and uncertain returns as compared with other occupa- tions. it appears to be a general experience that wherever by the extension of communications industries or commerce come close to agriculture the latter declines and begins to lose its best brains, its capital and its men. the lure of the cities is prover- bial, but the fundamental factor is economic; unorganised agri- culture cannot pay the wages obtainable in the organised indus- tries. the decline in the agricultural population of great britain and the united states is the most marked, but it 1s significant that in france, where of all countries the farmer is most pro- tected and prices have been maintained, the peasants are leaving the land for the growing industries, their places being taken in the south at least by italian immigrants.! iittensive production.—lt the land area for cultivation cannot be expanded the production from the existing area can be inten- sified, and it is evident from the most cursory examination of the yields of wheat in different countrics that a great intensification of yield is easily possible. the select areas of holland, belgium, denmark and scotland average 40 bu. to the ac.; england pro- duces 32, the world’s average is in the order of 12. ‘turning to potatoes the british average yield is 6} tons per ac., though good potato growers expect 10, the average in many of the large pro- ducing countries, ¢.g., france and the united states, is less than 3 tons per acre. intensification of production involves, however, increased cost of production per unit unless in some way the system of farming can be changed. the much disputed law of diminishing returns comes into play, which states that if any factor of production be considered separately, e.g., cultivation, fertiliser or water supply, successive increments of the factor give rise to increases of crop that successively diminish. in other words it is the last bushel of corn that costs the most fer- tiliser to produce, the last hundred pounds of increase in a bul- lock that involves the largest consumption of food. this expres- sion of the law of diminishing returns is perhaps not literally correct, but of its general truth in relation to agriculture there can be no doubt. the best illustration of its validity on a large scale may be derived from the course of english farming after 1 france:— 1846 total population 35,400,000 rural population 26,700,000 1918 =total population 39,600,000 rural population 22,100,000 1921 total population 39,200,000 rural population 18,200,000 o4 the great break in prices that began about 1875. at that time the english level of production as indicated by the yield of wheat, 32 bu. to the ac., was the highest in the world, but the english farmer could not meet the falling prices by increasing his yield. instead he lowered his standard of cultivation and cheapened his costs. the average yields obtained remained about the same, 32 bu. per ac., because the acreage under wheat was contracted by more than one-half by the withdrawal of the poorer lands from the plough. to take another illustration, the cheap wheat which was forcing the english farmer out of wheat growing was not the production of heavier crops than he could raise; it was north and south american wheat from lands giving an average yield of about 12 bu. per acre. as lawes put it “ high farming is no remedy for low prices.” if then intensification of production on the existing farming land of the world is necessary, it cannot be obtained by mercly tuning up farming as it is carried on at present, by employing more fertiliser or more labour, unless there is a general rise in the price of produce to justify the expenditure. there may be adjustments in the system of farming, there may be scientific discoveries or an all-round increase of skill, whereby an increased production is obtainable without increased cost, in which case the law of diminishing returns does not come into play or is dis- guised. but the probability is that such changes will come slowly; farmers all the world over are naturally conservative and disinclined to alter their proved methods, and under present conditions it would appear that a sharp rise in prices is a neces- sary antecedent to a wholesale movement in the direction of intensified production. the introduction of artificial fertilisers and imported feeding stuffs enabled the british farmer between 1840 and 1870 to raise the level of his production by something like one-half; what further advances may be expected from science in the direction of intensification? conservation of fertility-—-doubts have been expressed as to conservation of the fertility of the soil, but that fear may be dis- missed. the introduction of leguminous crops into the rotation suffices to maintain a stock of nitrogen sufficient for the present average level of production, and from this source alone the soil of the old settled countries has maintained its power of produc- tion over many centuries. the latest extension of this principle has been the growth of lupins over the sandy soils of the northern european plain to be ploughed in as a preparation for the rota- tion of grain and fodder crops, with, as 4 result, a definite increase in the fertility of german and [polish soils. an intensive agri- culture requires more available nitrogen than can be thus ob- tained, but this is assured by the many processes that have now been worked out for the fixation of atmospheric nitrogen. con- centrated nitrogenous fertiliscrs are becoming cheaper and more abundant, and the supply can be made to keep pace with almost any demand conceivable. phosphates cannot be manufactured, but great deposits have already been revealed, and more will doubtless be discovered. ; most soils under cultivation, however, stil] remain compara- tively deficient in phosphates, and, as hopkins of illinois so strenuously preached, if this deficiency be made up and legu- minous crops are grown, the production of the middle west soils can be maintained indefinitely even above its present level. on most soils the needs for potash are less, but the deposits of stass- furt and alsace, with the potential supplies from the undeveloped fields of spain and elsewhere, are so vast as to assure a supply for the most intensified agriculture for a long time to come. the only obstacle to an all-round increase of crops by a greater use of fertilisers is the question of cost; as yet the grain raised on the new lands, cropped extensively at a low level of production with- out fertilisers is cheaper than that obtained from yields with fertilisers; hence progress depends upon the power of the indus- trialist to cheapen fertilisers rather than upon the farmer. nor can much change be anticipated in the allied region of feeding stuffs, since they also are the product of cultivation. economics in conversion.—great economies are possible in the conversion of feeding stuffs into meat; a calculation made agriculture in war time showed that the amount of meat, milk and other animal products realised in great britain during the five pre- war years was only about 3 of what might possibly have been obtained from the fodders consumed. but improvement in this respect will be the outcome of exact individual management rather than of any sweeping change of method, and the whole field is influenced by the economic consideration that it is often more profitable to let animals grow carelessly and wastefully on wide pastures rather than to spend labour on husbanding their resources to the full. still the progress that has been made in america, the scandinavian countries and great britain in the exact rationing of milch cows in proportion to their yield indi- cates the economies that could be effected. the aim of the agriculture of the future will be to economise man-power as the expensive item in cost of production, and the value of machinery lies in its power of reducing the labour frac- tion in the cost per unit of the article turned out. breeding.—genetics, the science of systematised breeding, has a great part to play. even amongst crops like wheat and barley, which have been worked at by so many generations of the old empiric breeders and which are therefore less susceptible to improvement, great advances have been made within the last half century, not so much perhaps in gross yield as in adapta- bility to climatic conditions and disease resistance. the breeding of marquis wheat has enabled the wheat belt to be pushed miles to the northward and added millions of acres to the potential wheat area, solely in virtue of its power of ripening a week earlier without loss or quality. the enhancement of the percentage of sugar in sugar beet from something in the order of ro to 18-20% is another example of the breeder's art, and similar improvements may be expected in other fodder crops which are often only the outcome of chance discoveries and accidental crossings. many of the tropical crops, like the coconut, have never been subjected to selection and are still as nature made them. the immediate task before the breed- ers is to reduce the old sound doctrine of ‘‘ pedigree’ to terms of useful performance only, to eliminate “‘ fancy ” points and to standardise our breeds for production only. but there is nothing basic, nothing immediately revolution- ary in these measures; the key to progress lies in the general adoption of more exact measures and in the education of the farmer to be ready to take advantage step by step of the small but cumulitive discoveries of the investigators. assuming that the progress of science is capable of bringing about great en- hancement of production by methods that do not immediately bring into play the law of diminishing returns, we may next in- quire whether the organisation of agriculture is adequate to the demands made upon it. small or large holdings —by far the greatest part of the farming of the world is carried on by peasant holders, using that term to denote men who cultivate their farms mainly by their own labour and that of their families. if we ignore the social and political considerations that com- mend peasant farming to the statesman, to what extent can it be expected to meet the growing demands of the world for food? it may be agreed that the division of a large farm into small holdings is generally attended by increased production, but that is because it involves a change from an extensive to an intensive system of farming, a change which was equally open to the large holder. the efficiency of the peasant is not as a producer but as a competitor who can undersell the large farmer because he 13s content to give a great output of labour, that of his wife and family as well as his own, in return for a somewhat bare living. but the large farm can be the more efficient if efficiency is meas- ured in terms of production for the labour expended. on the large farm alone can machinery and other labour-saving devices have full scope, and with the staple crops like wheat or potatoes the economy of large-scale working is obvious. even allowing for the detailed handling involved in stock feeding, milk pro- duction, truck and fruit farming, a higher level can be reached by the organisation and skilled supervision of a team than by single-handed working. large-scale operations for the amelio- agriculture ration of the land by drainage and kindred operations are as a rule only applicable to large estates, unless the state exercises a paternal and often uneconomic control over the land. it may be doubted, too, whether peasant communities are going to be as receptive of the advances of science and new developments as large farmers working for profit. however, the physical advantages of the larger farmer are very generally offset by his inability to get out of his men a day’s labour comparable either in quality or quantity to that given by the peasant. science and the art of management have not so far advanced as to drive the peasant worker to the wall; indeed, by his labour alone he is still able to undercut the large farmer and make him lose confidence in the power of organisa- tion and machinery. it is in agriculture as it was in the textile industry a century ago, the hand loom weavers can still live alongside the power-mill and even break it by their competi- tion. it is indeed one of life’s ironies that just at the time when the advances of science are putting new powers at the disposal of the entrepreneurs of land, labour should be acquiring a new class-consciousness which renders it reluctant to co-operate in any experiment in large-scale farming. yet it is only by develop- ments of this kind that agriculture would be enabled to pay industrial rates of wages. at present the vicious circle is com- plete; low prices and the wage threat hold off the capitalist from any adventure into agriculture, while the same low prices pre- vent the present-day farmer from paying any higher wages. in despair a solution is being sought in a reversion to peasant farming whereby the land is put into the hands of men who have, hitherto at any rate, been willing to give an ample day’s work for an uneconomic return as measured by modern standards. it is often maintained that a peasant community can be united into an efficient agency of large-scale production by means of co-operative organisations, which ensure not only a proper mar- ket but also that degree of control of the individual producer that is desirable for his commercial welfare. co-operation.—a firmly established co-operative society can buy for the farmer the best type of seed and can almost insist on his growing it; it can enforce upon the farmer standards of cleanliness and quality in the milk produced, it can set out the particular type of pig it is prepared to market and say in what way it should be fed. and the co-operative society can exercise this wholesome pressure without hurting the independence of the farmer. co-operative organisation by binding the farmers into efficient commercial units and by exercising pressure and persuasion in the direction of better technique may outweigh the mechanical disadvantages of the small farm, because it pre- serves individual initiative and the willingness to work charac- teristic of the peasant. some organisation of marketing is essential to the farming of the future, otherwise even the large farmer is powerless against the growing combinations developed by international commerce, powerless also to meet the fluctuations of production that are inevitable in agriculture. since the farmer cannot regulate his production because he has to make his preparations long before the market is declared, since he has to adopt a routine suscep- ttble of change only at considerable intervals of time, combina- tion in marketing alone can save him from the damaging effects of seasonal over-production. it may seem idle to take precau- tions against over-production when the whole world is calling for supplies and a possible scarcity of food has to be contem- plated. but it is just these over-productions, temporary, sea- sonal and local as they may be, that destroy confidence in farm- ing and hinder its orderly expansion. combination there must be, whether of small farmers moved by the spirit of co-operation or of great agricultural enterprises actuated by business intelli- gence. control too may be predicted, whether it is control exercised by farmers themselves from within or by some external authority, for the present haphazard system with its destructive competition bet ween individuals and between nations only results in keeping agriculture at a low level while people want food. see also co-operation; farm organisation; tarmers’ organisations; foop supply; grain; land tenure, etc. a, bibliography.—e. m. east, afankind at the crossroads (1923); t. h. middleton, food production in war (1923); m. whitney, the soil and civilisation (1924); e. g. nourse, american agriculture and the iuropean market (1924); q. e. baker, ‘© the potential supply of wheat,\" econontic geography, vol. i, no. 1 (march 1925); see also u.s.a. dept. of agriculture, agriculture yearbook, 1923 and 1924; international inst. of agriculture, rome, international yearbook of agricultural siattstics (1925) and the final report of the agricultural tribunal of investigation, cmd. 2145 h.m. ay cues london. (a. d. h.) ii. scientific developments the period 1910-26 saw unprecedented advances in agricul- tural science. until r910 the united states and canada were the only countries possessing adequate organisation for agricul- tural research. germany had a number of experiment stations staffed by enthusiastic workers making the most of their means, but great britain and france were both badly equipped. in 1909 the british parliament set up the development fund at the instance of mr. lloyd george, then chancellor of the ex- chequer, and assigned a capital sum of {2,900,000 for rural devel- opment, including agricultural education and research. under the advice first of sir a. d. hall and afterwards of sir t. h. middleton, the development commission made grants out of this fund to certain institutions each responsible for one or more sections of agriculture. in france, the conseil d’administration of the ministry of agriculture, under the presidency of m. roux, is projecting a national experiment station. in the british empire, canada has admirable agricultural colleges and experimental farms; india has the great experiment station at pusa, founded in 1903 with the aid of a generous gift by mr. phipps, an american; australia, besides its older universities and agricultural colleges, has the waite research institute at adelaide, founded in 1923; new zealand has the cawthron research institute at nelson, founded in 1915; trinidad has the imperial college of tropical agriculture, founded in 1924; while throughout british africa, notably in the union of south africa and the sudan, there are important laboratories and research stations. the tropical research station founded by the germans at amani has now passed into british hands. in the united states, agricultural research, already strong, has been considerably strengthened by increased appropriations, the estimates for the dept. of agricul- ture in 1924 amounting to no less than $42,000,000. side by side with these scientific activities, there have been marked developments in implements, including tractors, culti- vating and draining machinery, milking machines, harvesting implements which not only cut, but thresh the grain as they travel, throwing out the sacks of grain on the field; and many other appliances. these implements are not as efficient as good workmen in the performance of individual operations, but they achieve more work in a given time. the results appear rather in the reduction in the hours of labour necessary to secure a given crop, than in any increased production per acre. a few crops show increased yields, ¢.g., in great britain potatoes and wheat, but most do not. the human labour has, however, been greatly reduced without sacrifice of crop. further, the losses through adverse seasons are diminished; there are now no catas- trophes like that of 1879. insect and fungus pests are distributed all over the world by modern transport, but their activities are being controlled. crop propuction the main advances in crop production are due to: (1) a better knowledge of the properties of soils; (2) greater supplies and greater knowledge of fertilisers and other methods of increasing plant growth; and (3) the introduction of varieties of crops better suited to the local conditions. the soil facors.\\—the soil provides water and nutrients, but it must also allow liberal access of air to the roots, and be free from any harmful substance or obstruction limiting full root development. the quantity of water needed by the plant 1s considerable, usually exceeding 300 times the weight of the dry t for further information see sir e. j. russell, sot! conditions and plant growth (1926). 56 matter, or 30 times the weight of green crops (grass, cabbages, mangolds, etc.), while the amount of nutrients is less than 1/100 part of their dry weight. indeed over a great part of the culti- vated land of the world deficient water supply is the principal factor limiting crop production. air supply is equally impor- tant; successful root development depends on an easy_interchange of gases between the atmosphere and the soil through the pore spaces which form 30 to 50% of its total volume. but these spaces also contain water, and in a wet soil air movement is much restricted; carbon dioxide then accumulates, and injures the crop when its quantity rises much above the normal (0-2 to o-5% by volume of soil air). freedom of root development necessitates an easy passage of the growing rootlets through the soil. this is secured in practice by bringing the soil into the friable, crumbly condition known as a good tilth. these three factors, favourable water and air relationships and a good tilth are closely linked; the connection has now been traced to the soil colloids. soil colloids.—soil consists mainly of mineral particles rang- ing from 1 mm. diameter to -oo1 mm. or less; a fraction, usually about 10% or less, has colloidal properties. part of this fraction is organic, part inorganic. the organic part is humus derived from decaying plant residues, principally from the lignin by oxidation. part of this is an acid, humic acid; much of the remainder is akin to an anhydride, for it is transformed into the acid by hot alkali; the acid appears to be tetra- basic and to contain carboxyl groups but no nitrogen (oden). in the soil it is closely associated with a complex nitrogen compound, prob- ably protein. the inorganic colloid is the ultra clay or colloidal clay isolated by the sharples or other super-centrifuge. no sharp line divides this from the clay and fine silt of the older mechanical analysis; usually 0-001 mm. (=i) is taken as the conventional upper lmit. r. bradfield (missouri experiment station) shows that the clay isa salt of a complex alumino-silicic acid. in normal soils the base is calcium; the clay is then readily flocculated and conducive toa satis- factory tilth. but the calcium can be replaced by hydrogen forming an acid clay not conducive to good tilth, and having the undesirable property of combining with, and therefore taking from the plant, bases needed for plant nutrition. the calcium is replaced by sodium when sea water floods the land; or, in dry districts, where the irriga- tion water contains sodium salts (as it commonly does); or in ordi- nary practice where sodium nitrate is used too intensively on heavy soils. these base exchanges had long been known but not understood; they were discovered by the english chemist, way, in 1850, and studied in recent years by gedroiz at petrograd and hissink at groningen; but the reactive substances were not isolated from the soil. whether the colloidal clay is the only reactive body 1s not known. the colloidal clay has the properties of an electronegative colloid. it can be flocculated by acids or by salts, but is dispersed or detloccu- lated by the negatively charged hydroxyl! anions (e.g., alkalis), the phenomena are complex. the sodium clay is the most easily and the calcium the least easily dispersed of all the clays. calcium clay is the normal clay. in the course of their evolution plants have become adapted to it, and it is therefore the most fertile of all clays, conferring on soils the desirable water relationships. sodium clays, on the other hand, are the least suited to plants. ‘their easy deflocculation causes resistance to plant roots and filling of the pore spaces of the soil with water. worst of all, they readily hydrolise in the presence of carbonic acid and water to form sodium carbonate, a dreaded plant poison, the black alkali of irrigated soils. the rem- edy for these evils, adopted by the california experts, is to convert the sodium into a calcium clay by treatment with calcium sulphate (gypsum); the sodium carbonate and sodium sulphate simultaneous- ly formed is then washed away. the treatment is ineffective, how- ever, unless sodium salts are withheld from the soil. the colloids, both organic and inorganic, are distributed through- out the soil as a jelly-like coating on the surface of larger particles, or coalescing into smaller particles; their great power of absorbing water is the main factor in detcrmining the water-holding capacity of soils. these discoveries have found practical application. dryness in soil, a frequent source of infertility, is associated with lack of colloidal material and is remedied by adding more plant residues, either farmyard manure or green manure, the alternative of adding more clay being usually impracticable. in irrigation schemes care is taken to exclude sodium salts, not always an easy operation, because sodium chloride and sulphate occur widely in the dry regions of the world, no doubt as the residue of former seas. irrigation is combined with drainage to wash agriculture out sodium salts and facilitate re-formation of the calcium clay should the sodium clay arise. | | acidity or ‘‘ sourness ”’ in soil is now traced to the humic and clay acids; its quantity is ‘measured by a “ lime requirement ”’ method based on the power of the soil to absorb calcium from a solution of calcium oxide or bicarbonate; and its intensity by determinations of the hydrogen ion concentration in the soil. comparison between the two methods is complicated by the fact that the colloidal or other substances in the soil have a considerable ‘‘ buffer ”’ effect, but an expert analyst can form a fair estimate of the quantity of lime or of calcium carbonate needed to bring about a given degree of improvement. the organic matter of the soil is more than a source of colloids. being the remains of previous generations of plants it contains all substances necessary to the life of the plant, and, in addition, material synthesised by the plant during its life and still con- taining energy fixed by chlorophyl from the sun’s rays. in the soil this energy material supports a multitude of micro-organ- isms: bacteria, fungi, algae, also protozoa feeding on the bacteria, and numerous insects feeding on the organic matter or preying on each other. in obtaining food and energy these organisms decompose the complex organic matter and liberate the energy stored therein, the final products being cos, water, simple com- pounds of potassium, calcium, etc., phosphates and nitrates, all essential plant nutrients. thus the remains of one generation of plants afford food for a later generation; the transforming agents are the soil organisms which live on the energy and nutrients still remaining in the residues. the production of plant nutrients, while the usual result of the activities of the soil organisms, 1s not an essential consequence of their existence. in their search for food and energy they may leave nothing for the plant, or even take up some of the plant nutrients already in the soil. protein contains more nitrogen than the organisms need even after multiplying as much as the energy content allows; ammonia is therefore left for the plant. carbohydrates and cellulose on the other hand contain no ni- trogen, and the organisms, in multiplying up to their energy con- tent, absorb nitrates from the soil; the plant therefore suffers. this explains why addition of sugar to the soil lowers crop yields, and why straw, in spite of its fertilising constituents, does not increase, but may diminish crop yields. the realisation that the organisms do not always or necessarily produce ammonia has caused the abandonment of the old division of soil bacteria into ammonifiers and non-ammonifiers. while most, if not all, of the soil organisms can effect alterna- tive reactions for obtaining food and energy, certain reactions can be brought about only by a few specific organisms, among them the oxidation of ammonia to nitrate, which provides energy for the organisms, and the fixation of atmospheric nitrogen and its conversion into protein by azotobacter and clostridium, though these organisms, by preference, assimilate nitrate if they have the chance. other nitrogen fixing organisms live in the nodules on the roots of leguminous plants; the association is mutually beneficial because the plant receives nitrogen com- pounds from the organism and the organism receives carbo- hydrates from the plant. the number of organisms in the soil varies continuously. i there are great seasonal changes, the numbers being high in spring and autumn, low in winter and summer, as happens also for plankton in the sea and in fresh-water lakes and for algae in a pond. there are also great daily fluctuations. d. w. cutler and l. m. crump have shown that these are determined by fluctuations in the numbers of amoebae, thus confirming russell and hutchinson’s discovery of the importance of protozoa in the soil economy. ‘the meaning of these changes is not clear. three applications of soil microbiology are made in agricul- tural practice. simplification of the population by partial steril- isation results in a greater production of nitrate and consequently greater productiveness; the soil can simultaneously be rid of some insect or other pest. in glass-house practice soil may be heated by steam or treated with poisons such as cresol, carbon- disulphide, chlorpicrin, etc. these do not long remain in the agriculture soil, but are attacked by certain soil organisms and oxidised, presumably for the sake of the energy liberated. none of these methods is applicable to field conditions, but examples of the action are found in hot countries. a second application of soil microbiology is the inoculation of the seed of a leguminous crop with the organisms associated with it so as to ensure more vigorous or greater growth. this was attempted as far back as 1890, but without success. subse- quent laboratory investigations showed that the organism passes through several stages in the soil, only one of which is motile. for maximum effectiveness it is necessary to ensure motility; this is done by adding milk and phosphates to the cultures. difficulties of storage and transport of the organisms, which caused many of the best cultures to die before they reached the farm, have been overcome by storing the organisms in sterilised soil and transporting them on agar. the technical details have been worked out by bartel of stockholm, christensen of copen- hagen and thornton of rothamsted. inoculation of lucerne is now a recognised practice in scandinavia, and is spreading in great britain, the empire and the united states. the third application of microbiology is in the retting of plant residues to produce a humus manure. the heap is soaked with water and mixed with an ammonium salt and calcium carbonate; the organisms are invariably present, and need only the added nitrogen to set them working vigorously. a fertiliser resembling farmyard manure is thus produced from otherwise waste sub- stances. the use of fertilisers where water supply is not a limiting factor, crop yields can be considerably increased by the proper use of fertilisers. the problem of fertiliser supply, formerly urgent, has been profoundly altered by the world war, one of the chief agents with which it was fought—combined nitrogen—bcing also an important fer- tiliser, prior to the war chile was the main source of nitrate and coal of ammonia; synthetic nitrogen fertilisers were obtain- able, the industry having been founded as the result of sir william crookes’ impressive address at the british association in 1898, but they played only an insignificant part in farm prac- tice. during the war extensive factories for the preparation of ammonia from atmospheric nitrogen were erected in central europe and, since the war, in other countries also. three proc- esses are used: the arc process, yielding calcium nitrate, almost limited to norway where water power is abundant; the cyana- mide process, used in switzerland and other countries near a source of coal; and a catalytic process now becoming the most popular, usually a modification of haber’s, yielding ammonia which can be converted into the chloride by combining the process with the manufacture of soda, or into the sulphate by reaction with gypsum, or into nitric acid by oxidation. the effect of post-war developments is seen in the following estimates of the world’s production of nitrogen compounds:— compounds tn tons (2,240 1b.) of pure nitrogen 1924-5 igi2 1903 chile nitrate . . . 363,000 | 401,000 221,000 sulphate of ammonia by- product ; 290,000 | 247,000 108,000 fixation industry :-— arc process (nitrate of lime) : . : f 25,000 10,000 nil cyanamide« « «. + 115,000 19,000 nil catalytic sulphate of am- monia.. 255,000 |} nil nil other nitrogen compounds 60,000 | nil nil 1,108,000 | 677,000 329,000 the productive capacity is considerably higher than this; hence all fears as to supplies of nitrogenous manures have been banished. some of the nitrogen is used for industrial purposes and explosives, but agriculture took about 595,000 tons in 1913, of which 290,000 tons was supplied by chile nitrate, while it took 983,100 in 1924 5. germany uses more nitrogenous manure than any other country in the world, her consumption in 1924-5 being estimated at 335,000 tons of pure nitrogen, almost all of which was for agriculture; this a7 is greatly in excess of her pre-war consumption (225,000 tons!) and is more than one-third of the whole world’s consumption. new methods of manuring crops are being tried (see below, under sul phaie of ammonia), in order to secure the maximum agricultural output as a rapid means of increasing wealth. nitrate of soda.-—the fears once entertained of an early exhaustion of the chile nitrate deposits (1921 had been mentioned as a final date) have been dispersed by improved methods of extraction; in 1925 the prospects were so good that messrs. guggenheim, of new york, purchased large nitrate grounds and began erecting a plant for the operation of a new process not yet published. most companies still employ the old shank’s system; some use the more modern processes of gibhs or butler,? with what success, however, is not known. the price still remains above pre-war levels, while that of sulphate of ammonia has fallen; in consequence the consumption in great britain and ireland, which before the war was 80,000 tons per annum, has now fallen to 40,000 tons. nitrate of lime.—yhe norwegian product is entirely satisfactory; its calcium is useful on many soils and its solubility quickens its action. it usually contains 13% of nitrogen, and is thus somewhat less concentrated than nitrate of soda, which contains 15-5 %. inthe pure state it is hygroscopic, but this difficulty is now overcome. ammonium niivate.—this has the advantage of concentration, containing asa rule 34-8° nitrogen. its deliquescence was overcome by crystallising in a special way. [but it suffers from the insuperable disadvantage of being highly explosive when detonated, so that it is not likely to become popular as a manure. sulphate of ammonta.—this is now made neutral and is drier, more frialle, less sticky and more easily drilled than the old, which contained 0:03 to 0-05 % acid; it is also slightly more concentrated, e containing 21-1 ° nitrogen or 25} °%> ammonia against 20-8 % nitro- gen or 25!% ammonia. in the export trade it tends to cake, a cdlis- advantage that can now apparently be overcome. new methods of using it on grass land are being studied at hohenheim; large dressings are given to force an early growth of grass, which is first grazed, then cut for hay and finally grazed again. the system necessitates in- creased dressings of potassic and phosphatic fertilisers and also of lime. it is being tested at the dairy research institute, reading. great britain is the chicf exporting country and the united states comes second; spain, japan, java and france are the chief importers, using it for oranges in spain, rice in japan and sugar in java. con- sumption in great britain has risen from_40,000 and 50,000 tons in 1913 and 1914 to 153,000 tons in 1924. the price is now nearly at pre-war level and may fall lower. cyanamide is inconvenient and uncertain as a direct fertiliser; it is therefore usually converted into ammonia though attempts to overcome its disadvantages are still being made. . urea is the richest fertiliser in nitrogen (46-7 °,), a great advantage for export. it is also neutral, and unlike sulphate of ammonia, leaves no acid residue in the soil. as a fertiliser it is slightly inferior to nitrate of soda but not to sulphate of ammonia; it 1s better applied with the seed than used as a top dressing. superphosphate of lime.—one ton of sulphuric acid reacts with approximately one ton of mineral phosphate ta give superphosphate. the enormous consumption of sulphuric acid during the war caused a great expansion in productive capacity, which it was hoped would bring down the cost of the acid and therefore of superphosphate after the war. this hope has not been fulfilled; acid prices are still 50 to 100°, higher than the pre-war level. the process of manufacture has become greatly improved by the instalment of labour-saving devices and of fans to remove the fumes. basic slag has greatly altered since the war because of the dis- placement of the bessemer converter by the open-hearth process which yields a slag containing little more than half the phosphate formerly present. further, the fluorspar used in making much of the slag reacts with the phosphate—yielding a fluorapatite, thus lowering its sollbbility and fertilising valuc. mineral phosphates.—ground mineral phosphate was generally unsuccessful as manure before the war. the failure is now explained; the grinding was not sufficiently fine. good results are now obtained both on arable and on grass land with phosphate passing through a sieve having 120 apertures to the linear inch, instead of the old one with 100 apertures only. even so, however, the mineral phosphate appears to be inferior to superphosphate on arable land and to high soluble basic slag on grass land. potassic feritlisers——trior to the war potassic fertilisers were obtained only from stassfurt. three salts were worked: the sul- phate; the chloride or muriate and kainit, a mixed salt containing potassium and sodium chlorides and magnesium sulphate stand- ardised to contain potassium equivalent to 12-5 % of k2o. during the war the cutting off of german supplies led to exploitation of alternative sources, some of which were good. since the war stassfurt no longer monopolises the world markets, the french 1on_ the pre-war territory with 35,000,000 hectares of‘ arable land: the post-war territory contains only 30,000,000 hectares arable land. 2see j. b. hobsbaum and j. l. grigioni. jour. chem. ind. (jan. 1917). . 58 having opened up the mines of alsace. these deposits differ from those at stassfurt in containing neither potassium sulphate nor magnesium salts; hence they supply only the muriate or chloride of potassium and * french kainit,’’ a mixed salt of potassium and so- dium chlorides; stassfurt still therefore has the monopoly of the sul- phate and of magnesium salts. the sulphate and the chloride of potassium are on the whole equally effective in promoting plant growth (though in certain circumstances one is more effective than the other), but the sulphate is rather better for improving quality of potatoes, one of the most important crops for which potassic fer- tilisers are used. the consumption of potassic fertilisers has greatly increased since the war. other suggested fertilisers —magnesium sulphate has on occasion increased the yield of crops, but the conditions are not sufficiently well known to justify recommending its use by farmers. silicates have been tried as fertilisers, especially in germany, where it was hoped that they might partially replace phosphates and so reduce the need of importation, germany having no phosphate deposits; but these hopes have not yet materialised. manganese and boron are both essential to the growth of certain plants, but neither can yet be used by farmers. quality in crops —while quality is easily recognised by ex- perts, it cannot vet for any crop except sugar beet be expressed in chemical terms. quality is mainly determined by varietal factors, some varieties possessing it in greater degrees than others, but it is considerably influenced by temperature, water supply and soil type. increasing efforts are made by experts to improve quality. in sugar beet, the percentage of sugar has been stead- ily increased by using as seed producers only those roots found by analysis to possess unusually high sugar content. in 1871 the average percentage was 10; now it varics about 18 or 19. the roots can be sampled without impairing their value for seed pro- duction. in potatoes, cooking quality cannot yet be explained in chemical terms, but it is associated with variety and with soil conditions, the black fen soils giving high yields but not high quality, while the silts of the eastern counties and of the lothi- ans give both high yields and high quality. in barley, malting value also is not expressible in chemical terms but is associated with variety, with seasonal factors and with soil conditions. milling value of wheat seems to be mainly varietal; for long it was confined to the hard spring wheats of continental regions (e.g., red fife in canada), but it has now been bred into autumn wheat by biffen in his ‘‘ yeoman.” the effect of fertilisers on the quality of crops is less than was at one time supposed; nevertheless, fertilisers influence the character of the growth, and this reacts on the quality. more important effects are acceleration or retardation of ripening, tendency to strengthen or weaken the straw, and certain changes in the composition of leaf or secd. plant diseases and pests striking advances have been made in our knowledge of plant diseases and pests, and of measures by which they may be con- trolled. three general methods are adopted :— varieties of plants are sought which are immunc or highly resistant to the disease; if, as usually happens, these varieties lack some neces- sary or desirable character, they are crossed on mendelian lines with others possessing it. this method its being adopted in the canipaign against rust in wheat, one of the worst pests of this crop. it is also used against wart disease in potatoes, a fungus pest (syuchytrium fndobtoticum) which threatened terrible damage to the crop but has been rendered almost harmless by the introduction of immune varictics, the second method is to modify the conditions of growth so as to give the plant more vigour to overcome the disease. ‘his has been successful in glasshouse practice in dealing with diseases of the cucumber and the tomato.! the third method is to attempt a cure. fungi are commonly con- trolled by spraying with finely powdered sulphur, polysulphides or bordeaux mixture (copper sulphate and lime), the sulphur or poly- sulphides being used for the various mildews, and the bordeaux mixture for other fungi, e.g., potato blight caused by phytephihera infestans, and “leaf curls” on peach, almond and other trees caused by fixeascus defermans. insects are controlled by various sprays, the composition of which is determined by the nature of the insects and the state of the tree, #.e., whether carrying tender foliage or in its winter resistant state. eggs and sucking insccts, e.g., aphids, are killed by “ contact ”’ insecticides: alkali washes and coal- tar fractions or synthetic products in winter, nicotine and the various 1 see w. f. bewley, diseases of glasshouse plants (1923). agriculture tropical plants used by natives as fish poisons (derris, tephrosia, etc.) insummer. biting insects, e.g., caterpillars, are killed by spray- ing lead arsenate on to the leaves; this treatment should never be used after the fruit has begun to form, especially in dry conditions, as nothing more readily causes a scare than the discovery of arsenic on fruit exposed for sale. systematic studics of insecticides at rothamsted and elsewhere are bringing out effective organic compounds producible on the large scale. other methods of control are to find weak points tn the life history of the pest, the destruction of alternative hosts, and the search for hyperparasites which will greatly weaken the pest; this last is attractive but not yet successful except to a limited extent in certain islands, e¢.g., hawait. much trouble is threatened by mosaic and other diseases caused by unknown agents and therefore vaguely attributed to a virus. mosaic is transmissible by injecting a very small quan- tity of the juice of a diseased plant into a healthy one, and pos- sibly by aphids in their passage from plant to plant. weed control—the growing cost of labour has compelled farmers to omit some of the cultivations by which in past days weeds were kept down. four methods of control are adopted:— (1) certain free-seeding objectionable weeds are proscribed by law; farmers can be prosecuted for having them on their land. _ (2) threshing and seed-cleaning machinery have been greatly improved, so that seeds are now obtainable of a high degree of purity and entircly free from specified weed seeds. (3) effective machinery has been devised on the model of the horse-hoe for uprooting weed scedlings. (4) where the crop is already up and the weeds cannot be hoed except with difficulty, the whole ficld can be sprayed, at the rate of 50 gal. per ac. ,with a solution of either copper sulphate (3 to 5°), iron sulphate (10 to 15°), more popular on the continent of europe than in britain, or ammonium sulphate (30°), not yet commonly used; §°) sulphuric acid has eradicated bracken. these sprays need water, which is not always easily obtainable on the farm; dry sprays are therefore being used, especially finely powdered kainit (4 to 8 cwt. per ac.). for yellow rattle (rhinanthus crista-galli) in grass land, 6 cwt. powdered salt is applied per acre, and for daisics on lawns a mixture of dry sulphate of ammonia and sand (1:1 or 1:2) is sprinkled over the plants.? once the land is free from weeds it can be kept clean by growing dense crops such as mixtures of oats with vetches, etc., which smother any weed seedlings and can be cut for hay or made into silage. other methods of improving crop production a high tension electric charge has been found to add about 25% to the crop yields, but the process is not yet practicable on the large scale. radioactive fertilisers on this land are inefiective. suitable varieties of crops.—modern agriculture is becoming more and more a study in adaptation. instead of attempting by costly and laborious artifices to alter the soil or mitigate the effects of climate, farmers now seck out new crops or new varie- ties of old ones better adapted to their conditions than the old ones. this search for new varieties occupies much of the time of the research stations. binlriograrhy.—e, ramann, bodenkunde, 3rd ed. (1911); h. j. wheeler, afanures and fertilisers (1913); l. h. bailey, cyclopaedia of american agriculture (1917); hugh findlay, handbook for prac- tical farmers (1920); sir a, d. hall, fertilisers and manures, re- printed (1915); zhe soil, 3rd ed. (1920); f.s. marris, sed alkali, its origin, nature, and treatment (1920); sir e. j. russell, soi condi- tions and plant growth (1921); a. wulff, bibliogra phica .1 grogeologia, (wageningen 1921); l. h. bailey, cyclopuedia of farm crops (1922), cyclopaedia of farm animals (1922); t. l. lyons and h, o. buckman, the nature and properties of soils (1922); w. schneide- wind, die erndhrung der landwirtschafilichen kuliurpflansen (1922); w. f. bewley, diseases of glasshouse plants (1923); j. r. bond, farm implements and machinery (1923); a. bruttini, c'ses of waste materials (international institute of agriculture, rome) (1923); e. a. mitscherlich, bedenkunde, 4th ed. (1923); u. pratolongo, manuele di chemica agraria (milan 1923); j. a. 5. watson and jieax. more, lgriculture the science and practice of british farming (edinburgh 1924); w. j. malden, actual farming, 3 = . 975) plant breeding this ancient art, which by the end of the 18th century em- braced svstematic cross-breeding, received a great impulse from the rediscovery of mendel’s laws in 1900. in the past 20 years 2for further particulars sce w. e. brenchley weeds of farm land (1920). agriculture few agricultural areas have remained entirely unaffected by its exponents. three broad procedures are now recognised: intro- duction of crop varieties from other lands, which still bears fruit in newly developing areas; selection or the search for individual plants of especial merit in field crops, which has brought notable advances; and artificial hybridisation or cross-breeding, which stands first in importance. higher yield, better quality and resistance to disease have been the foci of effort. only time can establish the merits of new forms. official figures of acreage rarely discriminate between varieties, so that it 1s impossible here to mention more than the few more important but well proved advances. wheat.—wheat improvements take first rank, and among them the marquis wheat of canada is pre-eminent in point of acreage. in 1892, dr. wilham saunders crossed hard red cal- cutta, a commercial grade rather than a variety, and red fife, then the standard wheat of western canada. subsequently his son, dr. charles e. saunders, selected one type from the pro- geny. this became commercially established in canada in 1911 under the name of marquis. in 1917 it constituted 80% of the wheat of the prairie provinces. imported into the united states in 1913 it had, by ro1g, a spread of 11,900,000 acres. only one wheat is now more wide-spread in america; this is turkey, which, with twice the area of marquis, is a striking example of intro- duction, for it was brought from russia by mennonite immi- grants. earlier maturity, the primary distinction between mar- quis and the red fife and other wheats it has displaced, makes for immunity from rust, drought and frost. india, with great environmental diversity and characteristic impurity of native varieties, has proved a fine field for the breeder. under dr. a. howard, the pusa institute has established se- lected wheats which are ousting the older forms. pusa 12 and pusa 4 have an area of 500,000 acres in the united provinces, while punjab tr is grown in the canalised parts of the punjab on nearly twice this scale. helped by the provision of good seed, these new products are estimated to represent an annual gain to the cultivators of {£1,000,000. something of romance attaches to the introduction into ar- gentina of a wheat from the sze-chuan province of china. it has proved highly resistant to puccinia triticina, the rust which more than anything else threatened to suppress the great promise of wheat-growing in south america. the introducer, mr. w. o. backhouse, has now raised hybrids which, both rust resistant and generally superior, are fast becoming the standard forms. from the swedish station, svalef, have come a number of new wheats, barleys, oats and peas; swedish iron wheat has added to its laurels by gaining a hold in england. english millers, however, dislike the thick skin and quality of its grain. new wheats continue to be produced in england, despite the many years of improvement already passed. the little joss and yeo- man wheats bred by prof. sir r. h. biffen and introduced in 19t2 and 1917, are shown by an official return to occupy one- tenth and one-fifth respectively of the whole wheat area of the 14 principal producing counties. little joss, a hybrid from ghirka (russian), and square head’s master, is the only form grown in england with a definite resistance to yellow rust (puc- cinta glumarun). it has marked standing capacity and a curi- ously wide soil adaptation. yeoman is also a product of pre- meditated synthetic breeding. the parents were browick (eng- lish) and red fife—the world’s best bread-making wheat. heavy yield and great standing power are merits it shares with the best of the older forms, but its quality or bread-making ca- pacity has set a standard formerly believed impossible in eng- lish wheats. none of the older wheats can be used for bread save in admixture with stronger overseas kinds. inland millers pay heavy freights in bringing strong imported wheats from the docks to their mills. the all-english loaf is now being made commercially from yeoman flour, and by partial displacement of imported wheats from the inland millers’ blend is effecting a valuable cconomy. barley.—barley is of peculiar interest because the quality of beer- making kinds is nearly as important as the yield. at the end of the he, 19th century chevalier and standwell were the prevailing forms in ireland. archer barley was introduced from england in 1900, and irish archer, a selection made by dr. h. hunter, soon displaced the older varieties. an even more marked success attended his hybrid spratt-archer. spratt is an old form specially adapted to peaty soils: clistinguished by high yield, exceptional standing power and superier quality, it now occupies almost ga“, of the barley area of ° ireland. 1t is estimated that £40,000 spent on breeding and testing in ireland during the period 1905-25 has brought an increase equiva- lent to £250,000 per annum. contemporanecously the selections, archer and plumage, introduced by dr. e. s. beaven of warmin- ster, have contributed to the prosperity of english growers. the former includes the specially valuable character of short-necked straw by which the loss of ears in tempestuous weather, once very serious, has been much reduced. more recently, dr. beaven’s hybrid plumage-archer has come into cultivation. its improved quality and increased yield have given it an unquestioned pre- eminence on the heavier barley soils of fngland and scotland. roots.— roots, such as potatoes which flower uncertainly and mangolds whose varieties freely intercross in the field, are difficult subjects. but mangolds and swedes have yielded to that systematic patience which has done so much in danish agriculture. helweg, in denmark, first made clear that the only sound hasis of estimation for mangolds was yield of solid matter per ac. and not mere wet bulk, next he demonstrated that different forms or strains within any one variety might be widely divergent in gross yicld and percentage of solid matter. indeed, two strains of the same variety might corre- spond to a difference of £6-£8 in value of feeding material from one acre. the best strains were picked out, and by persistent teaching all bad strains were forced out of cultivation; good seed was ensured, and roots came to have a greater feeding value per ac. than corn. in england the area under roots is diminishing. in denmark it has steadily grown, and when the world war stopped the importation of feeding-stuffs it was roots that saved denmark. there was a time when wart disease (synchytrinm endobtoticum) appeared to threaten wholesale destruction of english potato crops. but steady produc- tion of immune varicties, reinforced by appropriate legislation, may . now be said to have brought seeurity to the one great crop in which that country is still self-supporting. other staple craps.—rice in malaya and south india, the millets in india, the fulghum oat of texas and kansas, the hybrid round- tipped tobacco of connecticut, svalef's victory oat, which has proved the best oat for england since abundance was introduced, and dr. c. a. barber’s new sugar-canes in india are among many other valuable new products of the last decade. some of these forms may soon be displaced by better. some may, in effect, suffer dete- rioration—a practical man’s belief which the scientist no longer entirely scorns. improvement is in certain instances largely attrib- utable to general betterment of husbandry and the provision of good seed. but that all these new forms have advantaged the culti- vator is beyond doubt. bripliograapuy.—a. h. reginald buller, essays on wheat (1919); h. faber, forage crops in denmark (1920); j. a. clark, j. h. mar- tin and c. r. ball, ‘‘ classification of american wheat varicties,’’ uls. dept. of agriculture bulletin, no. 1074 (1922); a. howard, crop production in india (1924); the organtsation, achievements and present work of the experimental dominion farms, govern- ment printing bureau (ottawa, 1924); f. l. pngledow, ‘ economic possibilities of plant breeding,’ preceedings of the imperial botuni- cal conference, 1924, cambridge university press (192 v3 l. ew) ase en animal breeding it must be frankly admitted that the expectations raised by the rediscovery of mendel’s laws have not been fulfilled. never- theless the conception that a stock animal should be judged by its progeny rather than by its ancestry or by its individual char- acters, a conception which owes its origin to experimental breeders or statisticians who have worked on mendelian lines, has given at least three results of first-class economic importance: cows of improved milking capacity, hens which lay more eggs and pigs which reach factory size in less time. it must be added, however, that improved methods of management in feeding, milk recording, trap nesting and egg recording have contributed largely to these achievements.! vitamines.—the discovery of vitamines has not fulfilled ex- pectations for animal husbandry. it is true that vitamine enthusiasts have brought to light many cases in which methods of feeding commonly used by owners of livestock result in pro- ducing symptoms of malnutrition, and more cases in which they do not yicld results as good as the feeder ought to secure. im- partial examination, however, shows (a) that farm animals are 1r.c, punnett, weredity in poultry (1923); f. 11. a. marshall and j. hammond, physiology of animal breeding, ministry of agricul- ture (1925). 60 much less affected by vitamine deficiency than are the rats, guinea pigs and pigeons, which were the subjects of the classical vitamine investigations, and (6) that farm feeding stufls are seldom or never really deficient in vitamines. in short, vitamines are not a burning question in the nutrition of farm animals. mineral requirements —the many instances of rations in common use failing to produce the expected result or even caus- ing symptoms of malnutrition, and the failure of the vitamine hypothesis to explain the facts, have focused attention on the much neglected subject of mineral requirements. close exami- nation of this question, more especially by orr and his colleagues at the rowett institute, aberdeen, has shown that most cases can be explained as being caused by a deficient or ill-balanced supply of ash constituents. there is no doubt that the modern deep-milking cow, the 150- or 200-egg hen and the quick-growing pig which reaches zoo lb. in six months, are excessively sensitive to ash deficiencies. there seems to be no doubt that the good results obtained by the use of fish meal for young pigs and laying hens are due in large measure to its high content of ash. in defining a balanced ration to-day, it is necessary to state not only the proteins, fats and carbohydrates, but also the ash con- stituents, and it must not be forgotten that even such elements as iodine and iron play their parts.! nutritive value-—about 1885 kellner showed that the real nutritive value of a feeding stuff was not the sum of the digest- ible nutrients which it contained. experimenting with about a dozen typical foods, he was able to measure their net nutritive value, which he expressed as the number of lb. of starch equiva- lent to roo lb. of the food. assuming that the difference bet ween the gross and net nutritive value was due to the work done by the digestive organs in disentangling the nutrients from the fibre, he devised a formula, based on digestible nutrients dis- counted for fibre content, for calculating starch equivalents of feeding stuffs. his starch equivalents thus calculated have re- ceived fairly general acceptance, and in fact are still the accepted basis for modern rationing. armsby and his colleagues, using quite a different method, have more recently measured net nutritive values, expressing their results in what they call calories of net energy. on theoretical grounds it has been shown that one |b. of knellner's starch equivalent is equal to 1,070 calories of armsby’s net energy. when converted by this factor into the same terms, kellner's starch equivalents and arms- by’s net energy for the same feeding stuffs agree in most cases. this is very reassuring, since it confirms the accuracy of both figures. cases in which there is significant disagreement are practically con- fined to coarse fodclers such as hay and straw, and there is no doubt that kellner’s figures are too low for such materials. armsby has shown that the difference between gross and net nutritive value is mainly duc to the large outflow of heat following a meal —rubner’s i teeter dynamic action—which results from the stimulus given to the animal’s metabolism by the absorption of the products by digestion. this being so, kellner discounted the gross nutritive value too heavily for the presence of fibre, and his starch equivalents of fibrous foods are in consequence too low. it seems to be necessary to raise the starch equivalent of good hay from kellner’s figure of 30 to at least 40, which is armsby’s figure, and probably to raise other fibrous foods in like proportion. growth.—comparative slaughter and balance experiments re- cently carried out have made it possible to calculate the com- position of the increase in live weight of sheep, cattle and pigs at various shapes of growth and fatness.? it is quite easy to con- vert composition into calories, and since one lb. of starch equiv- alent can produce 1,070 calories in the body, it is possible to set out a table giving the weight of starch equivalent required to produce one ib. of live weight increase in any animal at any stage of growth or fatness. such a table forms a logical basis for com- puting rations, provided of course the maintenance ration of the animal can be ascertained. the idea is the same as that under- lying the modern method of milk rationing by computing the ration on the basis of maintenance plus so much per gallon of milk yielded. this method, the scientific basis of which was a paper by kellner in rorr, is now widely used by progressive milk 1see dr. j. b. orr, the afineral elements in animal nutrition, presidential address section m. british assn. report 1925. 211. p. armsby and c. r. moulton, the animal as a converter of matter and energy (1925). | agriculture producers, and is perhaps the most valuable and practical out- come of modern nutritive studies. there is only one reason why rationing on the basis of main- tenance plus so much per jb. of increase should not come into equally general use, and that is the lack of accurate knowledge of the maintenance requirement of young animals. j-xisting tables of maintenance requirements have been calculated by rubner’s surface law from the results of experiments on adult animals, that they may be as much as 50 or even 100%% too low in some cases is indicated by du bois’ publications on the maintenance requirements of the human child and deighton’'s measurements of the basal metabolism of the growing pig. from deighton’s curve for basal metabolism it is possible to estimate the maintenance requirement of the young pig from weaning to factory size. this information and the caloric value of the in- crease provide a logical basis for rationing. no similar measure- ments of basal metabolism or maintenance requirements are available for growing calves, lambs or foals. ct. by aw.) iit. agricultural economics this important part of the article on agriculture is divided into three sections, dealing respectively with credit, insurance and prices. agricultural credit systems of agricultural credit may be broadly distinguished according to whether they are based upon a co-operative prin- ciple or not. co-operative credit has been successfully applied in europe (with the marked exception of great britain) and in india. in most of the newer countries the co-operative system has been relatively unsuccessful, and other means of financing agriculture have had to be found. the history of co-operative credit in the last 15 years records, almost without exception, an expansion of this system in countries where it had previously been firmly established; the number of rural societies has in- creased, and improvement and consolidation of central credit institutions have been effected. germany.—even in germany (the pioneer country in co-op- erative credit) which has suffered severely from the monetary disturbance due to the war, considerable expansion has taken place. out of the 38,coo agricultural co-operative societies reg- istered in 1924, 19,529 were rural banks, as compared with approximately 17,000 in to12. the difficulties of the post-war period were, however, very considerable. up to 1922, while prices were rising relatively slowly, the deposit of savings with the rural banks continued. but with the rapid collapse of the paper mark after that date the whole system became disorgan- ised; confidence was destroyed ancl depositors ceased to make the necessary investments. the shortage of capital thus brought about caused acute difficulty in the joint purchase of agricultural requisites, and many co-operative socictics were compelied to abandon it. plans were attempted to obtain working capital; membership was increased, and endeavours were made to attract capital with high rates of interest. none of these efforts, however, kept pace with the fall in values. ultimately, attempts were made to stabilise the system by abandoning the basis of the paper mark and placing the busi- ness of the co-operative societies on a rye, wheat or gold mark foundation. stability was ultimately introduced by the estab- lishment of the renten-mark, but the result was to disclose a shortage of credit in german agriculture, which led to serious difficulties in the sale of agricultural produce and the purchase of agricultural requirements. since then efforts have been con- centrated upon the restoration of the confidence of the rural investor, upon whom the system ultimately depends. shortage of money and high rates of interest have continued to be one of the chief difficulties of german agriculture, as also is the case with other countries of central and southeastern europe. france.—the conspicuous feature of agricultural credit in france is the state subsidy which it carries with it. under the 1 report of departmental commitice on rationing of dairy cows, ministry of agriculture (1925), *t. b. wood, animal nutrition (1924). agriculture meeline act of 1894 all or part of the members of one agricul- tural “ syndicat ” or more (sce co-operation, agricultural) could constitute a credit socicty, whose capital was obtained by subscription of members. the credit society became a “ filiale ” of the syndicat. a considerable growth of these societies took place with the assistance of a voluntary organisation which prepared model rules. in 1897 it was made a condition of the renewal of the charter of the bank of france that it would place at the disposal of the state without interest 40,000,000 francs together with an annual share in the profits of the bank, for the assistance of agricultural credit. in 1899 regional banks were created, the members of which were the local credit societies, and the above subsidy enabled the regional banks to reduce their rate of interest to the credit societies and consequently to pro- vide cheap credit to farmers. the number of regional banks in 1921 was 69, with nearly 5,000 credit societies affiliated to them. the extension of the system to the provision of long-term credit was made under acts of 1910 and 1920, which now permit a maximum loan of 40,000 francs to individuals to facilitate the acquisition and management of rural properties. these loans are for a maximum period of 25 years with interest at 2° (or 1% in the case of military pensioners or civil victims of the war). great britain.—great britain has no standard machinery of agricultural credit, the ordinary joint stock banks and trades- people providing the bulk of credit to farmers. in 1923 the agri- cultural credits act was passed with the objects (1) of enabling persons who had bought their holdings during the currency of the corn production acts—april 5 1917 to june 27 1921, when prices were exceptionally high—to obtain mortgage loans from the state, repayable within a maximum period of 60 years, and (2) of establishing co-operative credit societies empowered to borrow from the state, the latter are based on limited liability, cach member being entitled to hold an unlimited number of £1 shares upon which 5s. is paid up. the societies are empowered to borrow from the state {1 for each share so held. the act has not, however, been a success. as regards long-term credit for the acquisition or improvement of agricultural land, the principle widely adopted in european countries is one under which credit institutions lend money upon first mortgages on farm lands and buildings, and raise money for the purpose by the issue of bonds to the public secured on these mortgages. institutions of this character are to be found in germany (landschaften and mortgage credit banks), austria, hungary, czechoslovakia, italy, denmark, etc. in many cases these are of early origin, but since the war, particularly in the countries of central europe, they have suffered severely from shortage of money, and the high rates of interest have been a scrious handicap to agriculture. in a few cases efforts have been made to sell land bonds in forcign countries. cinited states —agricultural credit in the united states has undergone extensive reform as a result of important legislation passed during the period 1910-25. under the federal reserve act, federal reserve banks (of which there are 12) areempowered to discount “ eligible paper ”’ as defined by the act for “member ” banks in their district. farmers or other individuals must apply to their local banks which, if they are members of the federal re- serve system, may rediscount with the federal reserve banks the notes, drafts and bills of exchange acquired from their cus- tomers. under the federal reserve act, the term of discount for paper drawn for agricultural purposes was six months as against a three months limit on commercial paper. the former was extended by amendment of the act to a period of nine months. the agricultural credits act of 1923 also extended the definition of agricultural paper, particularly as regards co-operative mar- keting associations. the act of 1923 extended the facilities for ‘ intermediate ” credit by establishing 12 intermediate credit banks, the primary function of which is to discount for or purchase from banks, trust companics, livestock companies and other bodies, notes, drafts and bills of exchange, the proceeds of which are to be used for agricultural pur- poses. they may also make loans direct to co-operative associations. these intermediate loans have maturities between six months and three years. in order to increase their loanable funds, these banks oi are empowered to issue collateral trust debentures which are exempt from taxation, up to 10 times their capital and surplus, lastly, as regards long-term credit, the federal i'arm loan act (see federal farm loan s¥stem) passed in 1916, established a system bearing some resemblance to the german landschaften. twelve federal land banks, each operating in a separate dis- trict, are empowered to make long-period loans based on farm mort- gages, and to issuc bonds to the public, which are tax exempt, up to 20 times their capital and surplus. the borrower must join a farm j.oan assn. through which he obtains the loan. the farm loan assn. is essentially co-operative in form—each association guaranteeing its own mortgages. each federal land bank also guarantees the bonds of the others. in addition to these, legislation has provided for the formation of “ joint stock land banks” which are em- powered to make loans direct to individuals based on specific farm mortgages and to raise money for the purpose by the issue of tax exempt bonds in the same manner as the federal land banks. a certain amount of creclit is also furnished through co-operative chan- nels, 19 states having passed legislation providing for the organisa- tion of credit unions. these unions have some resemblance to the co-opcrative credit societies in lurope, and raise money for making small loans by the sale of shares and by receiving deposits. the organisation of credit unions as separate agricultural institutions has, however, made only a limited progress up to the present. canada.—iiin canada credit unions have been more successful, and over 150 with a membership of more than 66,000 have been organised since 1906, mainly in quebec and neighbouring provinces. by a number of acts the provinces of canada have also sought to extend the facilities for short-term credit to farmers. ‘these include the livestock encouragement act, 1917, of alberta, under which persons may form an association and jointly apply to the livestock commissioners for a loan; the livestock purchase and sale act, 1913, of saskatchewan; the rural credits act, 1917, of manitoba, and a similar act in alberta, both designed to promote co-operative credit. mention should also be made of the ontario farm loan act, the agricultural development act and the agricultural develop- ment finance act, all passed by the ontario legislature in 1921— designed both to assist land settlement and to provide short-term loans. as regards long-term credit, legislation has been enacted by the separate provinces. manitoba passed the manitoba farm loan act, which became effective in 1917, and was subsequently amended in 1919 and 1921. the act established the manitoba farm loans assn., which serves as the lending agency between the provincial government and the farmers, and is governed by a board of five members including a commissioner of farm loans. loans are secured upon first mortgages on farm lands and are repayable by annual instalment in 30 years. saskatchewan has passed legislation on similar lines (the saskatchewan farm loan act, 1917}, and alberta has followed the general lines of the farm loan act in the united states. anstralasia.—the development of agricultural credit has_re- ceived, and is still receiving, a considerable amount of attention in australia and new zealand. mention should be made of the agri- cultural banks act, 1923 (queensland), the object of which was to make provision for state advances to co-operative companies and associations and to farmers and others; the co-operative, commu- nity settlement and credit act, 1923 (new south wales), which amended the law in regard to co-operation and made provision for the formation and management of co-operative socictics, including rural credit societies, and the rural credit associations act, 1922 (new zealand). more comprehensive legislation is contemplated. india.—the development of agricultural credit in india has mainly followed the i:uropean model, and has made consistently steady progress. the first act legalising co-operative credit socicties was passed in rg04. this act was replaced by an act in 1912 which cluscly followed the english friendly societies act and permitted other forms of co-operation, the number of rural credit societies under this act excecds 40,000 and these are mainly modelled en the raitleisen plan. agricultural insurance the risks against which farmers are mainly concerned to pro- vide are those incurred in growing, harvesting and storing crops, animal diseases, condemnation of carcasses in slaughter-houses and those risks commonly covered by ordinary life, accident and property insurance. the nature of the risks to which farm- ing is exposed vary between one country and another according to its situation and climate. ‘thus losses from windstorms are more common in north america than in many countries of eur- ope (it has been stated that between 1916 and 1923, 752 torna- does occurred in the united states—an average of 94 annually); in great britain animal diseases, and in scandinavia forest fires, are more important risks, while in canada damage by hail causes heavy losses to farmers. insurance against these risks may be carried out either through ordinary joint-stock insurance companies, or through farmers’ 62 mutual insurance societies. both methods are used, but the latter is held to have certain advantages. many agricultural risks are, however, of a kind which differ from the risks of fire and accidents, in that the loss of a relatively large amount of property may occur at the same time. this is the case with windstorms which may affect a large area, with hail and with animal diseases which often take the form of epidemics, causing the loss of a large number of livestock within a short period. for this reason local mutual insurance societies operating in a small area frequently cover the risk by re-insurance. crop insurance.—the insurance of crops after harvest is a rela- tively simple matter, and the risk—mainly a fire risk—is often cov- ered by ordinary joint-stock insurance companies. the insurance of growing crops is a more specialised business. under this head the most successful development is that in respect of hail insurance. in the united states 43 joint-stock fire insurance companies, 41 mutual companies and four state insurance departments carried hail risks estimated in 1919 at $560,000,000. in canada the hail insurance district of alberta was formed under the municipal hail insurance act of 1918, having in 1919 67 municipal districts. ilail taxes are paid by ratepayers to the municipal districts which in turn pay to the municipal board. the total risk borne by the hail insurance board for the four years 1919-22 amounted to $72,000,000. in saskatchewan the municipal hail insurance assn. carried an insur- ance of about $25,000,000 in 1921 and 1922. hail insurance in europe has been developed to a less degree, but organisations to cover this risk are to be found in germany, austria, denmark, switzerland, france, spain, italy and elsewhere. in france 29 mutual societies existed for this purpose in 1921, and [taly had 51 socictics in 1922. a certain amount of hail insurance was effected in england in the counties of bedfordshire and huntingdon- shire after severe storms in 1906, but since then the matter has been allowed to decline. while hail insurance is the outstanding example of successful crop insurance, some progress has been made, particu- larly in the united states, in the provision of frost insurance. but more hope is attached to the development of comprehensive crop insurance policies, covering all the principal hazards. several attempts have been made by joint-stock fire insurance companics and others in the united states to develop a system of comprehensive crop insurance, but it is still in an experimental stage. there appears at present to be little development in this direction in europe. livestock insturance.-—yarmers in aggregate have large sums invested in livestock which is hable to suffer loss by discase and other causes. insurance against these risks through mutual insur- ance socicties or otherwise has made greater progress in certain european countries than elsewhere, although the united states has some 30 mutual livestock insurance companies. france provides perhaps the leading example of furopean livestock insurance; its development has depended partly on state subsidies. out of the 14,896 subsidised co-operative insurance and re-insurance socictics in france in 1921, over 10,000 were socicties for the livestock insur- ance, and 78 for reinsurance. the annual premiums are fixed by rules of the societies at not less than 1° of the value of the animals in the case of socictics which insure cattle only, 1°5%> for societies insuring horses, mules, etc., 1:25 %o for societies insuring cattle and horses, 3°5%o for societies insuring pigs. the amount of compensa- tion varies between 50°, and 80% of the net loss—.e., the value of the animals affected after deducting the value of the carcasses. in certain circumstances other methods of calculating the compensation are allowed. the re-insurance socicties cover certain defined arcas, and may either contribute to the settlement of all losses falling upon the affiliated socicties, or limit their contribution to such local societies as have had to pay compensation up to a sum in excess of a given rate. the affiliated societies contribute a certain proportion of the premiums to the re-insurance societies. jocal societies may obtain from the ministry of agriculture grants of two kinds (1) establish- ment grants, made to societies in the course of formation, and (2) grants for losses incurred, made to societies in full working order which have suffered unusual losses. similar grants may be made to re-insurance socicties, co-operative insurance in germany has not made progress com- parable with that of other forms of agricultural co-operation, only a small fraction of the livestock in the country 1s covered by insur- ance. in certain states, notably baden and bavaria, cattle insur- ance has received state assistance, and insurance of carcasses against condemnation by the sanitary authoritics has also been adopted ona small scale. | in great britain certain joint-stock companies specialise in live- stock insurance in addition to covering ordinary accidents and fire risks, while there are also a number of mutual societies for the insur- ance of livestock. there appears, however, little inclination on the part of british farmers to take advantage of these facilities except in the case of pedigree cattle or other valuable stock, the number of mutual societies registered and the membership having declined since 1913. there are, however, a considerably larger number of unregis- tered societies, such as pig clubs and cow clubs for the insurance of a prosperity without parallel in its history. agriculture their members’ livestock. it should be mentioned that under the diseases of animals act, 1894, compensation is payable by the state to the owner of cattle slaughtered under the act, in cases of foot- and-mouth cisease, swine fever and other diseases. ‘ fire insurance.—this is almost universally undertaken by the ordinary joint-stock companies but in some countries, notably the united states, it has also been largely developed on a co-operative basis. indecd mutual! fire insurance is one of the most successful as well as one of the oldest co-operative services which has grown up in that country. in 1924 there were about 2,000 farmers’ mutual fire insurance companies carrying risks amounting to over $8,000,000,000. these societies operate largely on an unlimited liability basis, a relatively smail number only limit the liability of members to a fixed suin per annum. the first mutual fire insurance companies in the united states were formed more than a century ago. an interesting branch of agricultural insurance is that connected with forest fires in scandinavia. organisations for covering this risk have been formed in sweden, norway, denmark and finland. the norwegian society for mutual insurance against forest fires formed in 1911, covered risks in 1923 amounting to 335,000,000 crowns, while a similar society in finland issued policies up to 653,000,000 crowns. agricultural prices the outstanding event in regard to prices of agricultural commodities during the vears under review is the upheaval due to the war. in practically every agricultural country, the prices of farm produce rose rapidly from 1914, during the war, and up to 1920, and fell—even more rapidly—between the spring of 1920 and the end of 1922. although other factors entered into it, the primary cause of this movement is widely recognised to have been monetary, that is to say, it was due to the almost universal monetary inflation which took place between 1914 and 1920, and to the monetary deflation which followed it. this is illustrated by the fact that the prices of agricultural produce, as measured by index numbers, have moved over the whole period in close harmony with prices of general commodities. the following table shows for the years 1914-22 inclusive, the percentage rise and fall of british agricultural prices (aiin- istry of agriculture and fisheries index number) and the per- centage rise and fall of general wholesale commodities (the sfa- tist’s index number) in each case based on the average of 1911-3 as zto:— agricul- wholesale | agricul- | wholesale year tural commod- | year tural commod- produce ities | produce ities 1qt4 1 2 i91i9q 158 147 i9i5 2 30 1920 1q2 201 1916 60 63 1921 11g 86 iqi7 ol ito 1g22 69 57 i9qi8 |e fe 130 au : after 1922 prices have remained relatively steady. the general form of the price movement illustrated in this table is to be found in the case of most other civilised countries. the exceptions are germany, russia, poland and some of the minor european countries, where the general price level continued to rise after 1920 1n consequence of the continuance of monctary inflation. in russia there was a great disparity between the two price levels owing to special considerations, the level of wholesale prices rising out of all proportion to the prices of agri- cultural produce. but elsewhere the gradual rise of prices, in- cluding those of agricultural commodities, from ror4, reaching a peak during 1920, followed by a rapid decline ending in most cases in 1922, was the common experience of each of the follow- ing countries: the united kingdom, trance, sweden, norway, denmark, switzerland, holland, spain, italy, the united states, canada, india, egypt, japan, south africa, australia and new zealand. although this was the form of the price movement, its extent and also the rapidity with which prices rose and fell differed between one country and another; the agricultural con- sequences of the price movement have therefore also differed. the upward price movement was accompanied by general agricultural prosperity; in the united states of america it was the downward movement was accompanied by scrious and in some cases disas- trous depression. in canada, the united states and certain other countries, however, agricultural prices fell during 1920 and agriculture i92r more rapidly than the prices of general commodities; in great britain they fell less rapidly. this meant that in addition to suffering the disabilities inseparable from a falling price level, agriculture in the former countries experienced a further difh- culty by reason of the decline in the purchasing power of agri- cultural produce—the amount of other commodities which could be exchanged for a given amount of agricultural commodities. for example, in 1919 prices of farm produce in america stood at 131% above the level of 1913, while prices of all commodities were 106% above 1913. in 1922 the former figure had fallen to 33 and the latter to 49. the fall in the purchasing power of the “farmer’s dollar,’ was therefore a potent factor in the agri- cultural crisis which developed in america after the spring of 1020. the curve in the general price movement of 1914-22 was partly due to the fact that the rise and fall of the prices of goods and services which the farmer had to buy—land (rent), labour, trans- port, seeds, fertilisers, feeding stuffs, etc-— lagged behind those of farm products, and secondly, that in agriculture the period of turnover is long. thus in the case of great britain, in 1919 the prices of agricultural produce were 158% above thes pre-war (1911-3) level. in the same ye ear agricultural wages were 96%, fertilisers approximately 100%, feeding stulls 1537°% above pre- war level, while the cost of rent and of rail transport had hardly begun to advance. in 1922 when agricultural prices were 69°4 above pre-war, wages were 74%, fertilisers approximately 52°, feeding stufis 49%, railway transport about 73 vo above pre-war, while rents had advanced roughly by about 15°%. in addition to this many of these costs of production were incurred many months before the produce was sold, and the effect of this was to increase the margin of profit in the upward movement and to decrease it in the downward. in actual fact these conditions led to a very large volume of agriculiural produce being produced during 1920-2 at a loss, not only in great britain but in many countries overseas. this was the primary cause of the almost world-wide depres- sion of agriculture which began in the spring of 1920. but other factors contributed. the stimulus of high prices and increased profits during and immediately after the war, reinforced by the failure of russia and danubian countries, led to a rapid exten- sion of the area under arable crops in certain countries. ‘taking the principal wheat exporting countries—the united states, canada, the argentine, australia and india—the total area under wheat in 1918-9 had increased by nearly 33,000,000 ac. above the average figures for 1909-13; in 1923 they were about 28,000,000 ac. above this average. during the general decline of prices, there was both a falling off in consumption and recovery in european production. in addition to this the world’s harvest of 1923-4, particularly in canada, was an exceptionally good one. the result was that supply excceded demand, and the general depression of prices consequent upon monetary deflation in 1920-2 was succeeded by a further depression of wheat prices due to increased production. the same applied in a greater or less degree to the other corn crops. asa consequence, a very acute situation developed amongst farmers of arable towards the end of 1923; in the wheat belt of the united states the crisis reached alarming proportions, and many of the banks concerned with financing farmers in this area, being unable to stand the strain, failed to meet their liabilities. the general level of agricultural prices in great britain re- mained fairly steady in 1924, the chief event being the upward movement of grain prices towards the end of the year. the world’s wheat area in 1924 showed a slight decline over that of the previous year, but the world’s crop was substantially smaller, the average yield being only 88° of the 1923 crop. the result was to correct the abnormally low level of grain prices in 1923 and to bring the price of wheat approximately to the level of other agricultural commodities. this improvement in prices brought considerable relief to the great wheat-growing countries, 1 the subject is discussed in the agricultural situation by warren & pearson, ch. 8, wiley & sons, new york, and in report of the joint commission of a 'gricultural enquiry, part i. 63 particularly the united states, notwithstanding the fact that the purchasing power of farm produce as a whole still remained below its pre-war value. in regard to the countries which continued monetary inflation after the war, the course of prices was entirely different, and the crisis of 1920-3 was not experienced. but a situation of a differ- ent kind developed later in consequence of the degree to which the value of the monetary units ultimately fell. germany may be quoted as an example. the rise in prices continued compara- tively steadily up to 1922, but after that the movement gained enormous momentum. the paper mark sank to a mere fraction of its pre-war value and with it invested savings often disap- peared. this is what happened in the case of the rural credit banks, and when stability was ultimately restored by the intro- duction of the renten-mark, agriculture was found to be seri- ously short of working capital. farmers, in order to raise money for future operations, began to throw large quantities of produce on the market, with the result that prices fell. this in turn brought about a wide discrepancy between the prices of things the farmer had to sell and the prices of those he had to buy. in pans 7os4: the prices of potatoes were 96%, rye 89%, fat- tened stock 73° of pre-war value, while superphosphates were 183%, machinery 664%, potash 105° and ammonia 96°% of pre-war prices. biprrocraruy.—c, r. fay, co-operation at ilome and abroad (1908); r. ml. cahill, da uquiry ante agricultural credit and a gri- cultural co-operation in germany (1913); m. t. herrick and r., ingalls, rural credit (1914); r. r. enfield, the slgriculitural crisis 7920-23 (1924); g. f. warren and f. a. p earson, the agricultural siuation (1924); hw. c. taylor, outline of a pricultural econonites 192 ae the numerous official papers, etc., the following may be mentioned: american commission to investigate and study agri- cultural credit and co-operation, lgricultural co-operation ond rural credit in europe (1913-4); international review of a gricul- tural heononiics, ¥ arious numbers (1916-25), gives a large number of references inc luding countries not specilically mentioned in this article; ministry of agriculture and fisheries, agricultural statistics (1920 4); report of the joint commission of agricultural in- quiry (u.s.a.), part l., the agricultural crisis and its causes (1921); ministere de 1 avriculture, li gislation relative au credit mutuel et & la co-operation agricole (paris, 1923); agricultural tribunal of in- vestigation, final report (1924). (r. e.) iv. electric power in agricvlti ure the domestic and industrial uses of clectric light and power have developed greatly in towns. there has been less progress in the country, owing chiefly to the high relative cost of distribu- tion where the demand 1s small and scattered over a wide area. use of electric power.—electric light and power have been found very uscful on farm premises where current is available. good light is as beneficial in a farmhouse as in an urban dwelling, ina cowstall asin a factory. the electric motor is simple, robust and easy to start; it gives a steady pull, and, with the usual charge ranging from 13d. to 3d. an electric unit for power, it is cheap to work. barn machinery —farmers rely on an oil-engine which is used (roughly in proportion to the acreage of the farm) to drive what is called barn machinery, 2.¢., chaff-cutters, root-pulpers, cake and oat crushers, etc. these machines absorb from 1 to 5 h.p. according to size. on a grass farm, the engine, perhaps 13 to 3 h.p., may work only for two or three hours a week in winter and be hardly used in summer when all the stock is out on the pastures. the annual consumption may be something like 1 h{.p. hour per acre of land or, say, 600 h.p. hours per square mile of country, equivalent to 450 clectric units of kilowatt hours. on an arable farm, where there is much preparation of food, including perhaps the grinding of barley-meal, an engine of 5 to 8 ei.p. may work several hours a day, and the annual con- sumption amount to about 12 h.p. hours per ac., that is, about 7,000 ii.p. hours or 5,000 electric units per square mile. cultivatton.—the greatest consumption of power in agricul- ture is in field cultivators such as ploughing. on most farms, this work is still done by horses. the only places where they have been replaced successfully by mechanical power are in flat areas with large arable fields. there ploughing can be done more 64 economically by tractors on light land and by steam tackle on the heavier clay. on a farm where three quarters of the area is arable land, the annual consumption of energy in ploughing may amount to 15,000 to 20,000 h.p. hours per sq. m., and half as much again may be used for other cultivations, a total of 22,000 to 30,000 h.p. hours per square mile. thus, on arable farms the energy needed for field work is considerably greater than that required to drive barn machinery. electric. ploughing—electric ploughing is being tried in france, germany, italy and elsewhere, and is generally carried out by contractors. the most usual method is to haul the plough backwards and forwards by means of a wire rope pulled by a motor mounted on a wagon at each side of the field, just as in steam ploughing. in a modification of this method, a single motor only is used, the wire rope passing round four anchored pulleys, two of which are moved as the plough proceeds. ex- periments have also been made in which the motor is placed on a carriage attached to the plough, and current supplied to it through an insulated, flexible cable, which is unwound as the carriage and plough move one way across the field and wound up again as they move back in the other direction. costs.—it is difficult to get comparable figures of costs. a committee of the institution of electrical engineers (aug. 1925) quotes the prices of french contractors as 66 to 127 fr. per ac. for ploughing to depths of 6 to 14 inches. this, at a time when the external value of the franc was about 80 to the pound sterling, seems to be equivalent to 16s. to 32s. per ac., but internal and external values of a currency are different in times of rapidly varying exchanges. the quotations of east anglian contractors for steam ploughing range from 17s. to 25s. per ac. according to depth (say 8 to 14 in.) and soil. the cost to a farmer of ploughing with horses is generally reckoned at about 15s. for light and 28s. for heavy land per ac. but, if this too were done by contractors, something must be added for profit. both steam and oil engines have the great advantage of being self-mobile; they can move about the roads and on to the ficld under their own power. with electric ploughing, the need of taking wires to each field, the great weight of the motors and carriage, and the cost of hauling them about with horses or tractors, together with the rapid, depreciation of some of the machinery, militate against its success. it seems likely that, unless some new method or improvement is applied, electric ploughing will make no headway, and that the use of clectric powcr in agriculture will be restricted to the driving of stationary machinery. special machinery—rbesides the ordinary barn machines, less common implements must be brought under review. [or threshing corn, smaller farms mostly rely on travelling threshing machines worked by steam traction engines. some larger arable farms, however, have their own threshing plants. where current is available, the machine can well be driven electrically with a motor of from 12 to 15 if.p. according to size. it is stated that, owing to the steadier pull of the electric motor, better threshing is done than with a steam-engine. on certain farms, power is used in other special ways. for instance, where a tower silo is installed, power is wanted to cut up the fodder and to lift it into the silo. ensilage is sweet or sour chiefly according as it 1s made above or below a temperature of 47° c., and german experiments show that it may possibly be worth while to heat the fodder artificially by passing an electric current through the silo. artificial drying—expcriments have been made with some success, chiefly at oxford, on the artificial drying of crops by blowing hot air through them. the process is not yet fully under control, but if it becomes common, it will consume power. this can perhaps be supplied more conveniently by oil-engines, but in special cases electric motors may be used to drive the fans which blow the heated air through the stacks of corn or hay. special advantage —one advantage of electric current is that power need only be used to the amount actually required. motors of quite small size are made which will drive light dairy machinery, horse-clippers, fans for incubators, and other imple- ——— agriculture, census of ments which absorb too little power to make it worth while to start an oil-engine to run them. the number of such implements is sure to increase as electric supply becomes more common. as regards dairies, milking-machines and also separators, clarifiers and butter churns are very suitable for electric drive. dairy- men, and perhaps fruit-growers, may find it profitable as time goes on to install refrigerating machinery. this may give another demand for power on certain specialised farms. poultyy.—to turn on electric light in poultry houses on winter evenings and give the birds an extra feed is found to increase the number of eggs then laid. the rise in the total number laid throughout the year is insignificant, but, since eggs are worth more in winter, the redistribution more than pays for the cost of light, food and extra labour. incubators can more conveniently be heated electrically than in other ways; by passing heated air through the apparatus by means of an electrically driven fan, uniform temperature and efficient ventilation can be secured. plant growth—expcriments indicate that plant growth is stimulated by a high voltage current of some milliampe¢re per ac. passing as a discharge to the crop from a network of overhead wires, which are kept at 20,000 to 60,000 volts above the earth. application for six hours a day for one month early in the growth of the crop seems quite as effective as a longer treatment. with certain cereals, an increase in yield of 20% has been obtained, but the results are not always assured, and the matter is still in an early experimental stage. other experiments, carried out in america and elsewhere, show that electric light, both arc and incandescent, in greenhouses, has an effect in accelerating the germination of sceds and hastening the growth of certain vege- tables, the effect depending somewhat on the colour of the light. electric supply.—in the neighbourhood of towns, and in indus- trial and mining areas, farms can be and often are supplied with current from central power stations. most of these stations now pro- duce three-phase alternating current, and the corresponding squirrel- cage type of motor is very suitable for farm use. further develop- ments of this kind may be expected, but the purely agricultural de- mand is not enough tocarry a network of mains over the countryside. experience shows that the demand for light and power combined varies from 1,000 to 6,000 electric units per sq. m. in good agreement with the estimate for power alone from oil-engines, as given above. in towns, the consumption may be a thousand times more. again, for long distances, in order to economise copper, high voltages must be used; these are dangerous, and must be transformed to lower pressures for domestic or industrial purposes. transformers are ex- pensive, and no ordinary sized farm consumes enough power to carry the cost of a high voltage transformer. ilence arises the apparent absurdity that a farm with high voltage mains running through it may be unable to get power. but, where a chain of villages creates a considerable demand along a definite line, or where pumping or irrigation needs a steady supply of power, the distribution of central station current in rural areas may become possible, especially if pro- duced by cheap water power. village suppltes.—w here current from a large power station is not available, a village supply may be feasible; a considerable number have been successfully installed in england, some worked by small waterfalls, others by oil-engines. . if water be plentiful, turbines and dynamos may run day and night, and a very cheap supply be ob- tained; but in other cases the energy must be stored in batteries of accumulator cells, which are costly and short lived. whenever cells are to be charged, alternating current is, of course, inapplicable, and direct or continuous current must be used. private installutions.—when no public supply can be obtained, there remains the question of a private installation. if o¢casional power to drive barn machines alone is wanted, it is obviously better to drive directly from a small oil-engine. but, if good light be wanted, and use can be found for motors of fractional horse power in dairy or house, a private electric plant may be worth consideration. the dynamo is generally driven by a water turbine or oil-engine, but the use of windmills seems now becoming possible. (see also fak machinery and tractors.) brsliograpiy.—a. h. allen, electricity in agriculture (1922); r. borlase matthews, jour. inst. elec. feng. (july 1922); rk. w. trul- linger, amer. soc. of agric. eng., lincoln, nebr. (june 1924); c. dampier whetham, jour. roy. agric. soc. (1924); report of a committee of the inst. of elec. iing., journal of the institute (aug. 1925). (c. d. w.) agriculture, census of.—the nced for an international agricultural census has been recognised by everyone who has occasion to try to estimate world production, consumption or stocks of any agricultural, livestock or forest product that aicard—aircraft carrier enters into international trade. taken a census, others have taken censuses only at long and irregular intervals, and there is great diversity and lack of com- parability in dates, in methods, in data and in form of publica- tion in different countries. in a total of 201 countries, 140 have never taken a complete agricultural census. the date of ae last census in great britain was 1908; in germany o13 3.4 austria 1910; in italy 1918; in argentine 1914; in rumania eee in cuba 1899; and in france 1892. lack of uniformity exists in methods of collecting data, in data collected in censuses of dif- ferent countries, and sometimes even in different censuses taken in the same country. the international institute of statistics, at its meeting at brussels in sept. 1923, approved an exhaustive report by a group of experts nominated by the league of nations with professor umberto ricci as chairman, advocating the taking of periodical censuses and the improvement of annual! statistics in all coun- trices. the pan-american union, representing all american governments, which met at santiago, chili, in the spring of 1923, and the international congress of social economy, that met in buenos aires in 1924, adopted similar resolutions. each of these international bodies recognised the international in- stitute of agriculture as the organisation best situated to pro- mote improvement in national statistical services and the taking of periodical agricultural censuses in all countrics. in response to this expressed need the general assembly of the international institute of agriculture, in may 1924, adopted a resolution confirming the great utility that would result from a general agricultural census in all the states in 1930-1 under a uniform plan. it also called the attention of the permanent com- mittee of the institute to the importance of inducing the adher- ing governments to agree to take such a census, and of preparing a draft basis programme to be submitted in 1926 to a mecting of specialists to be designated by the respective governments, the agreed programme to be transmitted to the various govern- ments. the gencral assembly authorised a small allotment of institute funds for the expenses of the preliminary work, which _ was supplemented by funds supplied by the international educa- tion board and by the united states department of agriculture. work of the institute —the institute then communicated the resolution to the adhering governments and favourable replies were received from the majority. in may 1925 a director of the preliminary work was appointed, a small office organised and a programme of procedure prepared. this programme contem- erage on . the preparation of standard forms of census schedules. . the preparation of a glossary of well-defined terms used in the census. 3. the compilation of data on the taking of agricultural censuses, on production and international trade in agricultural, live stock and forest products in all countrics. 4. revision of the preliminary draft of questionnaire forms by statisticians of adhering governments, 5. discussion and final revision of the census forms by a com- mittee of agricultural statisticians in connection with the general assembly meeting at rome in april 1926. 6. explanation and promotion of the census project in all coun- tries through correspondence, publicity and personal visits of the director and his assistants. international statistics of agriculture are important in pro- moting and facilitating international commerce, and constitute a potent factor in the determination of prices of agricultural, forest and live stock products, and of food, clothing and raw materials in every country, because of the universal operation of the law of supply and demand, and of modern facilities for rapid communication and transportation. but to be of real value in- ternational statistics must be comparable, and the only way to secure comparability is through international agreement to take censuses the same year and according to a uniform plan. other important results of the universal agricultural census will be its influence in bringing about improvement in the annual statistics of agriculture in many countries, and the probability that the census of 1930-1 will serve as a precedent for future world-wide censuses at regular decennial periods. (l. m. e.) many countrics have never | 65 aicard, jean francois victor (1848-1921), french poet and dramatist (see 1.434), died in paris may 13 192i. aircraft carrier.— although, previous to the outbreak of the world war, various trials had been carried out with launching devices for flying seaplanes from off the decks of a battleship, the progress made was slow and it was not until just prior to the outbreak of war in 1914 that a vessel was taken in hand for conversion to an aircraft carrier. the british govt. then took over a tramp steamer which was subsequently named the “ ark royal” and fitted her with a flying-off deck forward and two cranes for lifting the seaplane inboard after returning from a flight. this vessel was completed at the end of 1914 and proceeded to the eastern mediterranean where she proved useful as an aircraft depet ship. “ campania.’—further seaplane carriers being needed, sev- eral cross-channel steamers and passenger vessels were taken over and converted into seaplane carriers. the largest of these, the “campania,” was taken up in 1915 and a large flying-off deck fitted forward for the purpose of flying seaplanes off wheel trollies. these alterations were completed early in 1916 and the vessel proved of such service that a demand arose for further similar vessels to accompany the british fleet at sea. “ conte rosse.’—the next vessel taken over was the italian passenger and cargo ship ‘‘ conte rosso,” renamed “ argus ” which was building in 1916 at the works of messrs. beard- more & company. a complete flying deck was fitted fore and aft with a hangar for stowing the machines under this deck. the funnels were carried up to the level of the hangar roof and then turned back to run horizontally beneath the flying deck to the stern so as to discharge all funnel gases abaft the stern of the vessel, fans being fitted to cause a good draught through these funnel ducts. for transporting purposes lifts were fitted from the hangar to the flying deck and cranes to lift the machines from the water. to enable machines to be carried on the deck in addition, wind-breaking palisades were fitted which could be raised simultancously to a height of 14 {t. above the level of the . flying deck. “ furtous.’—whilst the first trials of this vessel were pro- ceeding early in 1917 it was decided to appropriate the “ furi- ous,” then completing at messrs. armstrong’s naval yard for aircraft-carrying purposes. ‘this ship was originally designed as a large light cruiser to carry two 18-in. guns in single turrets, one forward and one aft. the first stage of conversion was to remove the forward turret and fit a flying-off deck and hangar, and from this deck seaplanes and aeroplanes could be flown off successfully. attempts were later made to land machines on this forward deck, but these were not successful and so later the stern 18 in. gun was removed and a big flying-on deck fitted, the two flying decks forward and aft being joined by a walking way around the mast and funnel. owing to disturbances set up by funnel gases and eddies around the funnel structure, this flying-on deck was not a great success and the ship was further re-constructed, being finally completed in 1925. this vessel was fitted like the “ argus ” with a clear fore and aft flying deck, the funnel gases being led out over the stern. “ hermes.’—about the same time as the appropriation of the “ furious ” for conversion, designs were prepared for a carrier named the “ hermes” and this was the first vessel primarily designed as an aircraft carrier. some six months after, the chilian battleship “‘ almirante cochrane,” building at messrs. armstrong’s works, was taken over for conversion and renamed the ‘* eagle.” in both these vessels a departure was made in the construction of the flying deck since a completely clear fore and ait deck was not fitted, as in the “ argus ” and “‘ furious.”’ the funnels and navigating positions were incorporated in an “‘ island ”’ arranged on the starboard side, thus giving a clear deck of a width slightly less in way of the island than just forward or aft of it. neither of these vessels was completed until 1924, and in the meantime ves- sels of this type received consideration at the washington con- ference, being defined as follows:— 66 an aircraft carrier is a vessel of war with a displacement in excess of 10,000 tons (10,160 metric tons) standard displacement, designed for the specific and exclusive purpose of carrying aircraft. it must be so constructed that aircraft can he launched therefrom and landed thereon, and not designed and constructed for carrying a more power- ful armament than that allowed to it under article 9 or article io as the case may be. articles 9 and 10 are as follows:— article 9. noaircraft carrier exceeding 27,000 tons (27,432 metric tons) standard displacement shall be acquired by, or constructed by, for or within the juriscliction of, any of the contractirg powers. air forces ency was to wait and see what the future disclosed rather than to base programmes of development entirely upon past experience. the nations therefore shaped their aeronautical policies with an open mind regarding the future, and in most cases refrained from radical adjustments and expedients which progress to date might have suggested as desirable. what may in externals appear stagnation is not necessarily so in fact. every forward step is preceded by much research and experiment before it 1s presented to the world as a concrete achievement. even by the aircraft carriers (1925) en eh ee se a —— ee | date of | length eons ene ee com- between breadth eee lol ion perps. british empire ft. in ft. in argus 3 iqi7 1918 535—0 68—8 flermes ‘ i9i9q ig24 548—o 7o—3 eagle = 1918 ig24 625—0 105—2 furious . i916 1925 735—o 88—o courageous 1916 | { being | 735—o 8i—o | recon- glorious . ; 1916 struct-| 735—-o 8i—o | ed united states langley ; : 1912 1922 520—o 65—o (converted) lexington : ; i9i9g bldg. 874—o i04{—o extreme saratoga . 1925 bldg. 74—o 104—o i-xtreme japan hosho 1921 1922 510—o 62-0 akagi - oh 1925 bldg. 820—o 103—o extreme kaga ; 1931 bldg. 700—o 100—o france bearn 1920 bldg. 560—o 89—o however, any of the contracting powers may, provided that its total tonnage allowance of aircraft carriers is not thereby exceeded, build not more than two aircraft carriers, each of a tonnage of not more than 33,000 tons (33,528 metric tons) standard displacement, and in order to effect economy any of the contracting powers may use for this purpose any two of their ships, whether constructed or in course of construction which would otherwise be scrapped under the provisions of article 2. the armament of any aircraft carriers exceeding 27,000 tons (27,432 metric tons) standard displacement shall be in accordance with the requirements of article 10, except that the total number of guns to be carried in case any of such guns be of a calibre exceeding 6 in., except anti-aircraft guns and guns not exceeding 5 in., shall not exceed eight. article ro. no aircraft carrier of any of the contracting powers shall carry a gun in excess of 8 inches. without prejudice to the pro- visions of article 9, if the armament carried includes guns exceeding 6 in. in calibre the total number of guns carried, except anti-aircraft guns and guns not exceeding § in., shall not exceed 10. if alterna- tively the armament contains no guns exceeding 6 in. in calibre, the number of guns is not limited. in either case the number of anti- aircraft guns and of guns not excecding § in, is not limited. -the aircraft carrier was thus recognised as a definite and essential unit in a modern fleet by the washington conference at the end of 1921, although the first practical vessels of the type had not been commenced until 1916, those previous to this being experimental and at the best only floating aerodromes with repair facilities. the other naval powers followed the british lead in the building of this type of war vessel, and the aircraft carriers in service and building in 1925 for all powers are shown in the table above. this table is restricted to aircraft carriers proper, the earlier smaller vessels, which are really aircraft tenders or depet ships, being excluded. (e. t..d’e.) air forces.—the world war provided a powerful stimulus to all branches of war flying, and great advances were made in technical equipment and experience. this intensive develop- ment led to constant changes not only in the practice but in the application of flying, so that when peace came it was expected that progress would be as rapid as in wartime. this led to a hesitancy on the part of most nations to commit themselves definitely to a rigid line of policy in aviation matters. the tend- displace- iforse- draught eee spee ar 1 one ment peed power moment feo. an tons knots 21i— 0 14,150 20} 20,000 | 2-4 1n., 4-4 in. a.a. 20 acroplanes 18— 7 10,950 25 40,000'}) 745-5 10, fein, ak 2i—il 22,790 24 50,000 | 9-6 in, 5-4 in. ala, 21— 6 19,100 3i 90,000 | 10-5-5 in., 6-4 in. ala. 22—- 3 18,600 31 90,000 ror ne 22-=— 4 18,600 31 90,000 seeks i9— o [2:00 its 7.160 | 4-5 in. 30 aeroplanes 30— 0 33,000 34 180,000 | { 8-8 in., 12-5 in. a.a, 72 acroplanes 30— 0 33,000 34 180,000 carries a catapult 20— 3 9,500 25 30,000 | 47-5°5 in., 2-12 in. a.a. 26 acroplanes. 30-0 33,000 a3 170,000 {| reported stowage for 50-70 acroplanes. 25> 0 27,000 27 60,000 29— 0 24,800 21 35,000 beginning of 1926 many war experiences had not been fully digested, nor their lessons properly formulated. analysis of available data, research and experiment, although less apparent, equals in importance the more tangible evidence of aeronautical progress. unlike armies and navies, air forces cannot be judged solely by what is visible to the eye. a policy readily adjustable to whatever changes the future may bring; an elastic organisation that lends itself readily to expansion; adequate provision for research and experiment; training facili- ties; a husbanding of the resources, industries and trades that subserve the needs of aviation, and the national attitude towards flying give a truer perspective of potential air power than mere numbers of machines. nor is novelty of type much to go by, since a machine that is ahead one day may be surpassed by others in a little while. policy and organisation are the most important criteria. two theories of control.—two different schools of thought exist in regard to the general principle that should govern the organisation, administration and development of air forces. one school regards flying as a science that can best be applied to war uses by entrusting armies and navies with its adaptation to their own respective needs. aviation is, accordingly, constituted a component of these services, and its application in war is gov- erned by naval and military considerations. although this system has certain advantages, in that it grafts a novel instru- ment of war upon an existing stem and so avoids the disadvan- tage of setting up an entirely new organisation, there is no doubt that it exerts a limiting influence. the soldier and the sailor naturally approach aviation from the angle of their own pro- fession, and view its possibilities in their bearing upon naval or military warfare. such advances as are made are likely to follow divergent courses. an apparently inevitable spirit of competition between armies and navies also leads to duplication and tends to deprive effort of its full measure of results. the other school considers that the air merits a profession of its own, and that untrammelled types of aircraft carriers fic. 1. h.m.s. “eagle,” port quarter view, showing flight deck. fig. 2. h[.m.s. “hermes,” bow view. fie. 3. h.m.s. “ furious,” latest british aircraft carrier. fic. 4. model of u.s. aircraft carrier, of the “saratoga” type. fic. 5. h.m-s. ‘ hermes,” showing aero- planes parked on flight deck. (figs. 1,2, 3 and 5. pholos by abrahams, devonport. fig. 4. courtesy of u.s. navy dept.) air forces devotion to the science and art of flying is necessary to do full justice to possibilities, not only in relation to war but as a factor in modern life. it accordingly seeks to concentrate all aeronau- tical effort into one main channel, with branches to the various departments which flying can serve. duplication can thus be avoided and the fruits of experience can be adequately considered and properly collated. i. great britain great britain was the first to gather together the threads of aeronautical activity and place them in the hands of a central authority; and at the beginning of 1918 the air branches of the admiralty and war office departments were amalgamated into the air ministry (g.v.). in april 1918, the flying branches of the navy and army were merged into the royal air force. the idea was not a new one, and, although the impulse of war made obstacles easier to overcome, it was not in war that the concep- tion had its origin. the sub-committce of the committee of imperial defence, charged in 1911 with the study of aviation in its relation to defence, mentioned in its report that such a step might be desirable when flying was more advanced. the germ of the idea is also to be found in the constitution of the royal flying corps, formed in 1912, with its naval and military wings. in this instance, however, the measure was too far in advance of the time to survive inter-service jealousies, and shortly before the outbreak of the world war the royal naval air service was formed, the royal flying corps becoming part of the army. as air warfare grew in volume and importance, the defects of the dual system. under war conditions became more and more apparent. full use of the nation’s resources was prejudiced, and civilian ministers were not only denied unanimous advice on air matters, but were sometimes forced to choose between discordant views and to settle vital differences of opinion. the drawbacks of this competitive system were particularly glaring in the matter of technical supply. improvement was sought in the principle of joint naval and military air boards to co-ordi- nate supply for the two air services. these boards had, however, no executive control over policy, and achieved but little. fi- nally the air ministry was brought into being as the only ap- parent alternative to the existing evils. although a war measure, the air ministry survived the peace, and administers not only the air force but controls civil aviation as well. it has, however, not been allowed to continue its exist- ence as a department of state without considerable hostility and adverse criticism. its chief opponents were the navy and army. with their establishments reduced to a minimum, and their budget grants diminishing every year, the older fighting services viewed with misgiving the allotment of funds to the newcomer. they argued that the main use of aircraft in war is to assist directly or indirectly the army and the navy, and that accordingly these services should have entire control of their respective air arms. the reply to this objection is that the con- quest of the air has disclosed possibilities which transcend the scope of land and sea warfare; that to narrow the view-point to naval or military problems is to bring their possibilities into a false perspective; and although that acrial assistance to the forces that fight upon the sea and on land is necessary, this need by no means marks the limit that should be set to aerial opera- tions. moreover, to regard the air merely as an auxiliary to the sea and the land is a dangerous doctrine, since circumstances may render naval and military operations secondary to those carried out by air forces. another criticism was that a separate air force is extravagant, since it involves additional overhead expenditure. the reply is that this is offset by the economy achieved in having a single authority dealing with air matters. one result of recognising aviation as a profession in its own right has been a breakaway from traditional practice in policing the british mandates in the east. security in thesc territories is the responsibility of the royal air force; aeroplanes are recog- nised as the chief instruments for the support of law and order, and military forces are used as auxiliaries. the measure has been justified by the great economy achieved. the development 07 of this conception and its successful application would not have been possible without an air staff. another result is a reversal of principle governing the air vis-d-vis the land and sea forces in the defence of great britain against air attack. instead of dividing the air into two portions, one above the land and the other above the sea, and making the army and navy responsible for their respective spheres, the air is regarded for purposes of national defence as a single field of activity. the air force is accordingly responsible for guarding against air attack, and such ancillary ground forces as may be necessary conform to air de- fence measures and it carries out its work under the orders of the air commander. | avtation in peace and war.—since it is sometimes claimed that a true appreciation of a nation’s air strength cannot be reached without taking into consideration the civil aspect of flying, it is desirable to note the relationship existing between the peace anc war sides of aviation. air strength is represented by air forces maintained in peace, ready to function the moment war breaks out. heavy losses in life and equipment are, how- ever, to be expected in air warfare, especially if the belligerents are at all equally matched. air power will, therefore, depend ultimately upon the means available for rapidly making good these losses—that is to say, upon a reserve of flying personnel and on a healthy aircraft industry. it is in respect of these two important factors that civil aviation must make its contribution to a nation’s air strength. hence the practice of granting gov- ernment subsidies to commercial air transport enterprises. it may, however, be a long time before civil aviation will occupy, in relation to air strength, a position analogous to that occupied by the mercantile marine in relation to british naval strength. the requirements of civil and war flying differ considerably. for commerce, economy in running and maintenance and pay- ing load are the factors that count most. for war, speed, climb- ing power, the carriage and use of armament, and fighting qualities in general are the chief factors that control design. consequently apart from the fact that they connote an aircraft industry and the existence of a potential reserve of pilots, aero- planes used for civil purposes do not contribute directly to a nation’s strength in the air. the roval air force the officers of the general duties or military branch of the royal air force are divided into two categories. about 50% of the total are those for whom the atr force provides a permanent career. practically all officers in this category must pass through the r.a.f. cadet college at cranwell. the remainder consists of officers serving temporarily in the royal air force; either those from civil life who engage for a period of five years on the active list followed by four in the reserve, or those seconded for a period of four years from the army or navy. the other ranks are filled either by boys who go through an apprenticeship in a trade at one of the boys’ training establishments, passing into the ranks on reaching the age of 18, or by men enlisted direct from civil life. the normal period of service is seven years with the colours and five with the reserve. in addition to the general duties branch of the royal air force, there are the stores, ac- counting, medical, dental and chaplain’s branches. units are divided into the following types:— table if, type of unit equipment fighter squadrons 12 single-seater fighting aeroplanes. i2 single-engine bombers, or bombing squadrons . 10 multiple-engine bombers. army co-operation squad- rons , ; : 12 army co-operation aeroplanes, — 6 aeroplanes, seaplanes or flying navy co-operation flights boats. fleet air arm 6 aeroplane flights in aircraft carrying ships. 68 _ directly under the air ministry are a number of commands embracing air force activities both at home and overseas. the following table indicates the various areas in question, and the composition of the different commands:— table it. inland area 2 fighter squadrons (directly under area head- quarters). group i 2 bombing squadrons; army co-operation squadron; armament and gunnery school; men’s schools of technical training. group 3 6 bombing squadrons; 2 flying training schools; experimental establish- ments. group 6. | 8 fighter squadrons. i fighter squadron; 2 bombing squadrons; flying training school; central flying school; electrica! and wireless school; 3 army co-operation squadrons; school of army co-operation. group 7 coastal area headquar- ters 4 fleet fighter flights; 2 reconnaissance flights; marine aircraft experimental establishment; flying boat development flight; r f. units in h.m.s. “ argus ”’ (aircraft carrier), and h.m.s. “ pega- sus \"' (seaplane catricr). group 10 . | coastal reconnaissance flight; 3 fleet spotter flights; 2 tleet bay le flights; air pilotage school; seaplane i training flight; school of naval co-operation. overseas commands middle east! 2 bombing squadrons; army co-operation squadron;| aircraft depdt; engine repair depot; flying training school; aden flight. fighter squadron; 6 bombing squadrons; army co- operation squadron; 3 armoured car companies; 4 infantry battalions. ‘iraq . 4 army co-operation squadrons; 2 bombing squad- rons. india mediterran- ean. i coastal reconnaissance flight; 2 fleet fighter flights; fleet spotter flight; 2 fleet reconnaissance flights; fleet torpedo flight; r. a. f. units in h.m.s. “‘ hermes” and ‘ eagle,” aircraft carriers. 1 army co-operation squadron; © armoured car company. palestine . in addition to the above the organisation includes a cadet college at cranwell, lincolnshire; a school of technical training for boys at halton, buckinghamshire; the staff college at andover, hampshire; and the royal aircraft establishment at south farnborough, hampshire. the following table gives figures relating to the three chief air forces in europe:— table iii. er tor for cees, ent air ane see total country action ee we ceo nee ation | tion chines officers} other | fight-/bomb-| ma- | ma- ranks ers ers | chines} chines great britain . | 3,000 | 33,000 | 144 266 132 118 660 france g60 | 19,778 | 180 256 |obs. 60 | 1,192 536 fight- ters 160 total ce ooo 5 eh ats italy! 2,640 | 29,226 702 513 315 1,530 1 according to 1926 development programme, air forces although all general duty officers are on a single list and are, with the exception of those in the fleet air arm, available for any form of work, the varied functions performed by the air force result in the division of its units into types, such as the fighter squadrons, {leet air arm, bombing squadrons, etc., according to the duties they perform and the aeroplanes with which they are equipped. officers, accordingly, become identified with the type of unit in which they have had the most experience, al- though rigid specialisation is discouraged as a general principle. (a. w. eh. e. w.) ii. united states when the united states entered the world war, the aviation personnel consisted of 65 officers and 1,120 men of the army and 35 oflicers and 163 men of the navy. when the armistice was signed, the army air service had reached a total of 20,000 officers, 600 cadets, and 164,000 men, while naval aviation had a strength of 6,716 officers and 30,692 men. at the declaration of war, the united states possessed about 300 training planes, of which many were of inferior types. at the time of the armi- stice, about 8,500 training planes had been delivered. the army air service had, in addition to these, about 3,300 service type aeroplanes, de havilland 4’s and ilandley-page bombers, while the navy had about 1,600 anti-submarine flying boats. uptothe armistice, 15,700 training engines and 13,396 liberty engines had been produced. the liberty engine development, in point of rapidity, cost and quality, was one of the most strikingly suc> cessful projects of the war. post-war problems ——at the commencement of the war, army aviation was under the signal corps, but during the war the u.s. army air service was organised to concentrate the administration of aviation personnel and equipment. in march 1918, the control of naval aviation was centralised in the office of operations under the director of naval aviation, where it remained until the organisation of the bureau of aeronautics in 1922. the close of the world war found the united states with a large number of aircraft on hand. these were primarily mili- tary and naval aircraft unsuited for commercial purposes. furthermore, in accordance with the war policy laid down, the types of aircraft built by the united states were limited to army observation planes, navy coastal patrol planes and training planes for both the army and the navy. the close of the war found the country therefore with a vast problem of developing and building military aircraft of many other types to meet the special needs of the army and the navy and also the growing demands of commercial aviation. in the meantime it was necessary, not only from the stand- point of economy but also from that of training, to utilise to best advantage the aircraft on hand. since the personnel of war-time aviation was recruited largely from civil life and de- mobilisation deprived the army and navy of the services of this personnel, it likewise became necessary to recruit and train replacement personnel. the government had the choice of operating the types remaining at the close of the war and build- ing more of the same types, or of operating war types to a limited degree and spending most of the available funds in the develop- ment of new types. since no war was threatened the latter pro- cedure was followed. development work progressed to the point where in 1926, in so far as quality was concerned, the united states was not exceeded by other countries, and where superior types might be built in quantities in relatively short periods of time. general principles —maulitary and naval aviation have two primary aspects, which may be characterised as air service and air force. by air service is meant that portion of the aviation activity which is auxiliary to the military and the naval estab- lishments, such as reconnaissance and the control of gunfire. by air force is meant that branch which contemplates offensive air measures, co-ordinated, of course, with the military and naval establishments. the u.s. national policy requires that naval aviation be maintained in the same degree of readiness as the fleet and in the same proportion of strength, and this is the theory air ministry—air power on which the government has been working. it is a fundamental principle that the best defence is a strong offence, and this implies that naval aviation must be prepared to take the offen- sive with the fleet. the country is open to invasion from the northwest, the northeast and from the southcast by overseas countries. in so far as aircraft are concerned, bases would be require: for such an offensive. with the fleet at sea fully equipped with its surface vessels, submarines and aircraft, no enemy could establish such bases. again, with the feet at sea with its own aircraft, the air force could establish its own bases and carry out its own offensive; but this offensive, in so far as aircraft are con- cerned, must be based primarily on the decks of the carriers of the fleet. in other words, aviation is an integral and important component part of both the military and naval establishments, and its best effort must be directed in conjunction with the army’ and the navy, and not independently. strategic considerations based on the present capability of aircraft require that the united states air force should be the naval air force, not a separate air force based on shore or on ships. on the basis of these fundamental conceptions, development has gone ahead with rapidity. the air forces of other countries (e.g., see france; iraty) are - discussed in the articles thereon under the sub-heading “‘de- fence.” for commercial aviation see flying. bibliography.—a. swectsen, the american air service (1919); sir f. h. sykes, aviation in peace and war (1922); repert of the international air congress (london, 1923). (w. a. me.) air ministry.—the british army and navy at the begin- ning of the world war in aug. 1914 had separate adminis- trative organisations for their air services which were the royal flying corps and the royal naval air service respectively. these were amalgamated early in r918 and the air ministry was formed. it is a state department and the secretary of state for air is the responsible cabinet minister. he is also president of the air council, whose functions are analogous to those of the board of admiralty and the war council. the air council.—tin addition to the president, the air coun- cil is composed of the under secretary of state for air, who must be a member of either house of parliament, four service members (the chief of the air staff, the air member for personnel, the air member for supply and research and the deputy chief of the air staff) and the secretary, a civil servant. the air ministry provides the administrative machinery for giving effect to the air council’s decisions and it consists of various main depart- ments. the directorate of civil aviation deals with all matters connected with the regulation of civil flying. it comprises an accident branch, which investigates the causes of accidents, whether to service or to civil aircraft; an air transport branch, and a licensing branch. the department of the secretary is charged with the internal administration of the ministry and is responsible for the general routine. included in the department are the directorates of accounts, contracts and lands and the meteorological office. the department of the chief of the air staff includes the directorate of operations and intelligence and the directorate of staff duties and organisation, which, in addition to the functions implied by its designation, controls the signalling branch. this branch deals with questions of wireless communication for both the royal air force and civil aviation. the directorate of works and buildings is also under the chief of the air staff. the depart- ment of the air member for personnel deals with the recruitment, discipline, general welfare and training of officers and other ranks of the royal air force. the directorate of medical services forms part of this department. the department of the air member for supply and research includes the following directorates: (1) the directorate of scicn- tific research and technical development, divided into branches which deal respectively with design, armament, instruments and scientific research; (2) the directorate of airship development; (3) the directorate of aeronautical inspection, which is respon- sible for the inspection of all materials used in the construction of aircraft and engines; (4) the directorate of equipment, which is responsible for the supply, storage and issue of all equipment for the royal air force. (a. w. h. e. w.) tur united states in the united states there is no department of the government corresponding to an air ministry as it exists in great lritain. instead of endeavouring to administer all aeronautic activities through one central organisation, the government has divided the administration into three main departments. military avia- tion is handled by the war department through the united states army air service. naval aviation ts administered by the navy department through the bureau of aeronautics. the only extensive commercial aviation activity is the united states air maul, administered by the post office department. this depart- ment announced a policy of transferring the operation of some of the air mail lines to private contract. proposed legislation in congress in 1926 contemplated the establishment within the department of commerce, of a bureau whose purpose it would be to foster commercial aviation. the geographic position of the united states largely dictated this general policy. as the country is not within close striking distance by air of any major overseas force, it has been the policy to develop air service and air force within the army and the navy rather than a separate air force with subsidiary branches in the army and the navy. since the types of aircraft required by the army and the navy must be specially designed to meet the re- quirements of each of these services, and since commercial air- craft have entirely different characteristics, this policy would appear sound. the acronautic activities of the different depart- ments have been co-ordinated through joint boards and through the national advisory committee for aeronautics. there are, then, two policies in the matter of administering aeronautics: the one, the british in which military, naval and commercial aeronautics and the separate air force are all con- trolled by an air ministry; the other, the american, in which military, naval and commercial activities have the initiative in development, each along its own special line, co-ordinating their efforts through co-operation, rather than as dictated by a single organisation. these two different policies are in accord with the methods of government of the two countries and are largely dictated by geography and by policy. cw, a. m.) air power.—the uses to which ability to fly have been put are threefold: tactical military employment, strategical military employment and social use. all of these may be ex- pected to increase. prior to the world war, flying was almost entirely self- educational; its military uses were largely experimental and its commercial value non-existent. nevertheless, the reconnaissance work carried out by the royal flying corps of great britain in 19t4 enabled sir john french, in his own words, “ to make speedy dispositions to avert danger and disaster.” but visual reconnaissance was only the first of the new tactical utilities; subsequent developments included aerial photography, artillery observation assisted by wireless telegraphy, attack on ground targets by bomb and, later, by machine-gun from low-flying armoured machines. air attack upon and protection of these services brought about air battles involving up to 100 specialised craft. special british night-flying fighting squadrons were organised, which, controlling from the air a conjunctive force of guns and searchlights, sustained an effective defence against enemy bombing formations. in the naval sphere both aero- plane and airship were successfully employed in submarine spotting and destruction and in the convoying of mercantile surface vessels. torpedo attack on ships was developed; and reconnaissance for the contesting fleets had a marked influence in the conduct of the naval campaign in european waters. yet the million hours flying on the western front did not give the fullest opportunity for tactical air employment. this is exemplified by the operations in palestine in 1918 when air su- periority protected and concealed a british independent cavalry 70 turning movement, and an air attack on retreating columns caused the abandonment of all enemy transport and a complete dislocation of the turkish plans of retirement. in short, tactical air units developed from an assistance to a vital adjunct to land and sea forces. even so their possibilities are only partially ex- plored and will undoubtedly increase in the future, prominent amongst the inevitable extensions being the use of troop-carrying aircraft to increase the mobility of armies. air straiegy.—in strategy, however, the air war demonstrated in greatest degree the possibility of revolution in military science. long-range bombing attacks on the industrial centres aimed at the morale of the enemy were first carried out by the germans; and, though counter-measures put a stop to these raids, their possibility necessitated the retention of considerable defensive forces in great britain until a late period of the war. and the effects of subsequent british strategic air power, though it was not systematically organised until the last year of the war, and though the armistice put a stop to its development, showed both military and political authorities alike that direct attack on the morale of enemy civilian population must be an inevitable accompaniment of any future war and that nations must pre- pare accordingly for this eventuality. air strength can be easily, cheaply and secretly prepared; its radius of action at the close of 1925 was approaching 1,000 m. at r50 m. per hour, and these figures will increase. it opens a new phase and sphere in warlike operations and entails a radical rearrangement of the fighting services and the alteration of the composition of armies by forcing them to take mechanical forms. in addition to being a vital adjunct to the senior arms it is likely to play an increasingly important strategic redle. an air offensive which is encountered in the air will compel the removal of seats of government and of defence bases beyond its radius of action. with an increased range of aircraft this zone of ineffectivity will extend. power in the air will dislocate all forms of communica- tion and, if it does not actually cut off the supply of food and raw material, it will render their transit precarious. air navigation may go far to assist the avoidance ot conflicts, but in time of war, in combination with chemistry, its pos- sibilities will only be countered by superiority in the air. the defence of the british empire in particular is growing more complicated. great britain no longer depends for its security on the sea. on the contrary, its geographical position and extent open it to military attack, and air power is essential to its secu- rity (see british empire: defence). two principles.—for the full future development of military air power two principles assert themselves; the radical revolution it occasions in the training for and practice of war and the necessity of advancing air power by forwarding the power of flight. success in military air forces does not depend on numerical superiority alone. air efficiency, hike naval efficiency, depends on the national aptitude and ordinary use in peace. the best airmen are those who are accustomed as a normal routine to flying in all weathers, and decisive success in air battles can only come from long training in the air. air-going services, both military and mercantile, are the source of air strength, and power of expansion must rest on a widespread civil aerial activity. progress and limitations.—a constantly increasing number of long-distance demonstration flights since 1918, including a flight round the world in 1924, have shown the technical pos- sibilities of aircraft as a means of commercial communication. more practical demonstration is provided by the 30,000 m. of air routes in regular operation in europe in 1925, extending from london to nijni novgorod and from helsingfors to malaga, and thence to dakar, and by the 1,000,000 m. flown by british com- mercial air services for every fatal accident. the limitations to the use of this social power at the end of 1925 appeared to be three in number. tirst, though the risk of accident was small, safety comparable with that of other means of transport had not been obtained. the remedy is further technical progress, particularly in securing by mechanical means much for which the human factor is still responsible. second, air raids strict regularity of service, an essential in successful transport endeavour, was absent. conditions of bad visibility still dis- located air services. allied to this defect was the inability to fly by night, with a consequent loss over long distances of a large proportion of the time saved by travel by day. these limitations are not applicable where fog is of rare occurrence, or where the competition of a highly developed ground transport does not operate. but, with few exceptions, such areas offer no traffic for which speed is essential and its cost economic. the remedy for these disabilities is again technical development which will allow for safe flight in conditions of bad visibility. the final limitation is economic. the cost of air transport in 1925 may be taken as some 5s. per ton mile and 5d. a passenger mile. on very few routes is there a regular commercial traffic for which such a rate is economic. the remedy is to attract ‘increased traflic by a more efficient service and to reduce costs of operation. technical progress is the source of both. of transport by airship nothing could be said with certainty at the close of 1925. for uninterrupted flights of 2,000 m. or more the airship suggests a means of high-speed economic opera- tion. such experience as exists shows a series of mishaps, in each of which an attributable and avoidable cause was present; and an unremitting caution in every detail of experimental op- eration is essential to progress. the military values of air - power are demonstrated, but not yet fully developed. its social value has yet to be proved; but it must be remembered that civilisation has been spread by the extension and development of means of communication, and there is no authentic record of 1m- provement in speed of communication being found and aban- doned. cre. fics.) see w. mitchell, wunged defence. 1926. air raids.— directly great britain came into the world war, the german high command began to encourage their public with prophecies of the havoc the zeppelins were about to work in england, but it soon became evident that for airships to fly in daylight over enemy territory was to invite disaster. hence, although reconnaissances over the north sea towards england were begun by airships, the first actual attacks were made by aeroplanes. raids in 1914-5.—in dec. 1914 a couple of bombs were dropped in the sea off dover, and three days later, on dec. 24, the first german projectile hit english soil. a few half-hearted aitacks by aeroplanes and seaplanes, made during 1915, were ineffective, and it was left to the hghter-than-air machines to cause the first serious damage. in the evening of jan. ig 1915 two naval airships approached the coast between yarmouth and cromer. ‘they separated and dropped bombs on both towns. four people were killed. on april 14, mathy, boldest of all german air commanders, commanding lo, made a considerable tour over the northern counties. on this occasion he was not particularly successful, most of the bombs falling harmlessly in open country, but the following night lo caused some damage in suffolk. the next four raids were similar. capt. linnarz, very active about this time in command of one of the military airships, succeeded in bringing his ship over the metropolis on the night of may 31 1915. there was on this night only one raider, armed with an inefficient type of bomb, but there were 41 fires while five people were killed and 14 injured. , further raids in yorkshire and kent on june 4 had little result, but two nights later mathy again attacked the north. he found hull, and killed 24 people, besides wrecking some 40 houses. another airship, lz37, that attempted to raid on the same night, was destroyed by lt. r. a. j. warneford, r.n., while returning home near ghent. the first serious military damage in england was done by a single ship that raided the north on june 15s. a series of nine raids took place in the latter part of tg15. it opened inauspiciously for the germans, a zeppelin engaged in bombing dover being hit by a 3-in. gun that had just been mounted there. she struggled across the channel, and was finished off by bombing aeroplanes. air raids london was reached on four nights during this period. on sept. 8 mathy bombed the city deliberately; the damage done amounted to more than £500,000. mathy also took part in the raid of oct. 13, when his ship hombed woolwich. on this occa- sion the casualties were 33 killed and 77 wounded. two buildings were destroyed, 20 seriously damaged, and there were 13 fires, the total damage being estimated at £50,250. raids of 1916.—the defences could do no better in the early raids of 1916. nine zeppelins manoeuvred over the midland counties on the last night of jan., one getting nearly to shrewsbury, and sg people were killed. out of 16 british acro- planes that went up in pursuit, 8 crashed on landing. a month later two airships were able to sit over iiull and bomb it from a low height, without any interference from the defence. irom this time, however, the defences improved. l15, one of the five ships that attacked on march 31 1916, was hit by the gun at purfleet; it was then attacked in the air by lt. a.de b. brandon, of the royal flying corps, eventually falling into the sea off the coast of essex. fifteen airship flights were made over england and scotland during this april. the british losses were 84 killed during the series. . further raids at the end of april were organised in conjunc- tion with the naval bombardment of lowestoft and yarmouth. a large number of airships took part, but the result was small. london was saved from bombing by its defences on april 25. one zeppelin was eventually destroyed on the coast of norway. an abortive raid on harwich was followed on aug. 24 by an attack on london by mathy. a determined attempt on london was carried out by 14 ships on sept. 2. the metropelis was undoubtedly saved by lt. w. l. robinson of the r.f.c., who attacked the military airship sli1. she fell, a burning mass, near cufiley, middlesex. on sept. 23 1916 11 airships ieft germany and the main attack was directed on london by three of the newest super-zeppclins. having crossed the essex coast shortly before 11 p.m., l33 was over east london ten minutes after midnight. were she dropped 20 bombs. london, however, was no longer the help- less mass of former days. the searchlights continually lit up the hull of the airship; she was badly holed by the guns, one of her engines was damaged and she began to lose gas and fly clumsily. to add to her miseries, brandon now brought his machine close up to her. for 20 minutes he stuck to her, pumping bullets into the fabric. as she laboured back towards the north sea, the crew threw out everything on which they could lay their hands. her commander crossed the coast at mersea i., going out due east. but the certainty that his ship would fall into the sea was too much for him; he turned her about and came to earth three miles inland near colchester. mathy meanwhile brought his ship l31, in company with l32, up the english channel and, turning in over the kent coast, passed straight over the centre of london. south london and the extreme north of the metropolis suffered severely; but, for some reason, mathy threw no bombs in the central districts. the handling of the companion ship, l32, was not of nearly so bold a character. her commander spent an hour circling about romney marshes. as he crossed the thames near dartford he was picked up by lights and attacked by guns. lt. frederick sowrey succeeded in setting the ship on fire in several places; she fell at billericay. the british casualties on this night were 40 killed. on the night of sept. 25, seven ships raided the north. mathy, on this occasion, took his ship on an entirely new line; he flew up the channel as far as the isle of wight, where he turned north and went over portsmouth. he dropped no bombs on the for- tress or dockyard. yet another serious attempt to bomb london was made on the night of oct. 1. eleven ships started from germany. mathy, in l31, came in over lowestoft about 8 p.x. and as usual steered an excellent course on london. soon after-passing chelmsford, however, he found that the outer defences on that side of the capital were ready for him. he therefore turned and steered northeast. turning again he flew southwest, in order to get into 71 position for his favourite dash down wind over the city. after drifting a few moments towards ware, he set his engines going and started for north london at full speed. suddenly a heavy gunfire was opened on him and he decided to abandon his attempt. sec.-lt. w. j. tempest came up to the ship at 12,700 ft. and brought her down in flames at tpotter’s bar. during the whole of this great raid the only british loss was one man killed. the defence of london had now definitely got the better of the lighter-than-air attack; after this period no german airship ever flew intentionally over the metropolis. deterred by the victory of the london defences, the germans turned their attention to the north for the final effort of 10916. they met with no better success. of the 1o ships that left germany in the course of nov. 27, 8 came over land. one was destroyed on the coast near hartlepool before midnight by capt. j. v. pyott of the r.f.c. another raider, l21, after a remarkable journey right across england to cheshire, was caught in the early morning, when she was leaving the coast at yarmouth. she fell into the sea from 8,000 ft. and sank at once. during 1916, 18 raids were made on england by aeroplanes and seaplines. the first aeroplane attack on london itself was made on nov. 28 1916 by a single machine; the only intimation was the fall of six small bombs between brompton road and victoria station. raids of 1917.— before the end of 1916 it had become evident to the german command that, if effective bombing was to be kept up on targets that were worth attacking, it would be neces- sary to try new methods. early in 1917, therefore, they began equipping a squadron with special machines suitable for bombing england systematically. the first attempt came on may 25 1917. the 3rd bombing squadron, 16 machines strong, left belgium early in the after- noon and made the coast about 5 p.m. there were thick banks of cloud over essex. the task of navigating to london was found too difticult and the leader had to give up the attempt. he there- fore turned south. bombs were dropped on the canadian camp at shorncliffe, where there were 100 casualties. the worst effect was produced in folkestone itself. one bomb fell in a crowded street and killed 33 people, mostly women. the second unsuc- cessful attempt was made on june 5; 18 machines bombed sheerness with some effect. the guns at sheerness succeeded in hitting one of the raiders, which fell into the river off barton’s point. london scriously damaged —the third attempt on london was more successful. the whole of the 3rd squadron started in the morning of june 13; london was reached a little before noon. a few bombs were dropped in the east end and near the royal albert docks; then, at a signal from the leader, the formation loosed 72 bombs over a small area having liverpool street station as its centre. the station itself was hit by three bombs. the casualties were severe, 104 killed and 423 injured. the next raid on london on july 7 wasalso successful. twenty- four machines started. the main body of 22 machines came to london. the city received 76 bombs, one of them starting a fire in the general post office; 46 persons were killed and 123 injured, 22 buildings were destroyed, and 87 seriously damaged, the total damage being estimated at over £200,000. the anti-aircraft guns fired a large number of rounds, but produced no effect. the failure of the defensive arrangements caused considerable agitation, and the british govt. ordered a complete reorganisa- tion. the london air defences were formed as a separate com- mand to include all the means of defence, both from the ground and in the air. gen. e. b. ashmore was brought from france to take charge of the new arrangements. the new arrangements were soon tested; on aug. 12 a party of nine gothas made the land near harwich. after following the coast to the blackwater, they turned inland for london. the communication system of the defence control worked well, and the squadrons immediately defending london were at the required height in time to meet the enemy formation. the german commander turned his formation about before reaching the outer line of guns. a number of bombs were unloaded on ree: southend as the enemy made off, and 32 people were killed. an attempt on aug. 18 was frustrated by bad weather. an abortive attack on the midlands by 8 airships on the night of aug. 21 was followed by the last day attack on england on aug. 22, when capt. kleine, commander of the 3rd squadron, started out with 13 gothas to bomb sheerness and dover. a number of naval machines turned the sheerness bombers from their objective, and the german formation, harassed by the british pilots, wheeled south by ramsgate. here the anti- aircraft guns, working with great accuracy, shot down two of the raiders. a third was shot down off dover. night attacks begin.—the first group of night attacks came in the beginning of sept. 1917 and one of these reached london itself. on the night sept. 3-4, about 10:30, hostile acroplanes were reported near the north foreland, and warnings were sent out by the central control a few minutes later when it was clear that they were coming up the thames. unfortunately there was serious telephone delay in getting the warning out at chatham, and before cover could be taken a bomb had fallen on a drill hall in which a large number of naval ratings were asleep. no fewer than 107 were killed and 86 wounded. although on this night the defence was ineffective, certain points gave hope for the future. three pilots went up in fast scout machines, and found that it was by no means impossible to handle them at night. the idea also was evolved of barrage fire, a curtain of bursting shell put up in the path of the raiders. the last raid of this moon period, on sept. 4, reached london. the barrage fire, organised since the previous night, turned back some of the pilots, but to raiders reached the metropolitan area. considering the magnitude of the raid, the damage caused was small, and the total casualties for the night included only 14 killed and 48 injured. favourable weather produced a sustained series of raids, opening on the night of sept. 24 with an attack on london by aeroplanes, in conjunction with an airship raid on hull and the north. nine at least of the pilots attempted to attack london itself, but considerable improvement had by this time been effected in putting up barrage fire, which was successful in turning back all but three of the attackers. although 27 english machines went up they failed to find any of the enemy; the gun- fire brought down one of the gothas, which fell in the river near sheerness. the attack on the north was carried out by ro airships under capt. peter strasser. although i{full was found, the raid had very little success. on the following night, sept. 25, 10 aeroplanes attacked, and 9 people were killed. the attacks were continued on the 28th, when some 20 machines came over; the night was cloudy and a few only approached london; they were all kept off by the barrage fire. the barrage was again effective on the following night, sept. 20. out of the 18 or 19 machines that came over only 4 penetrated far enough to bomb london. the dover guns did well, bringing one of the enemy down in flames. on the next night, sept. 30, five german pilots got over london and bombed places as far apart as highgate, edmonton and woolwich: 14 people were injured and two killed. the last raid of the series, on oct. 1, was made by about 18 machines. during these raids a large proportion of the attackers had been turned before reaching their target, but the defences were still far from complete. the barrage fire was expensive in ammu- nition and there was a doubt if the supply could be kept up. the defending squadrons had not reached the necessary efh- ciency in machines or pilots. the “ aprons,” a new defence dev ised after the raid of depts s; were only beginning to be installed. the central control as organised in sept. 1917 could give no information to pilots when - once they had been sent on their patrols, but schemes to rectify this had already been initiated. the airship raid of the night oct. rg-20 1917, which became known in london as the “silent raid,’ has points of special interest. eleven airships met on the evening of the roth off the yorkshire coast for an attack on the industrial centres of the air raids midlands. while over england, the ships flew well over 16,000 fect. at this altitude the efficiency of the crews was much impaired by height sickness and the intense cold. another and fatal con- dition was produced by the weather. near the ground the air was misty and there was very little wind, but at the height of the airships a strong gale was blowing from the north, and in this the zeppelins drifted blindly south. one airship passed over london without recognising it and dropped a few explosive bombs; one of 50 kgm. fell in piccadilly near the circus and caused some casualties. realising that, on account of the ground mists, searchlights would have no chance of lighting up a high zeppelin, the defence ordered them to remain covered unless an airship could be heard. london was saved from a combined attack and the raid ended in disaster to the attackers. one airship only returned to germany in the usual way; six got back after flying over holland or across the allicd lines. the remaining four were destroyed during the following day on french territory. acroplane raiding was resumed during the moon period at the end of october. an attempt on the 31st was carried out by 24 machines. considering that a good many of them got over london, the effect of the bombs was small, 8 persons being killed and 21 injured. the weather in dec. 1917 was sniageieatie and only three attempts were made on london. the defences showed steady improvement. two gothas were brought down by anti- aircraft gunfire during a raid in the early morning of dec. 6. on the night of the 18th one gotha was so damaged that it fell into the sea off folkestone and was destroyed. on this night the new giant aeroplane dropped one 300-kgm. bomb near eaton square, making a large crater but doing little serious damage. the whole raid, however, cost london more than £225,000, 42 build- ings being seriously damaged and 9 destroyed, while there were 13 fires. on dec. 22 the last raid of the year was frustrated by unfavourable weather; one gotha was forced by engine trouble to descend near margate, where it was destroyed by the crew. raids of 1918.—in the five aeroplane raids of the first quarter of 1918 there was a tendency to replace the smaller gotha machines by the new giants. a gotha was destroved by a defending aeroplane on jan. 28. during this raid a bomb dropped by a giant fell on a building in long acre that was being used as an alr-raid shelter, and 41 people were killed. ‘three giants attacked on feb. 16; the only one that penetrated to london demolished a house in chelsea hospital with a 300-kem. bomb. the raid of march 7 1918 was remarkable as being the only occasion on which aeroplanes attacked london in the absence of any moonlight. warrington crescent was terribly wrecked. to turn to the airships, raiding was not resumed until the nights of march 12 and 13 1918. both these raids were made at an immense height, and the damage did not amount to much. iive airships of the newest and largest type attacked the mid- lands on the night of april 12. the end of the airship raiding came on aug. 5-6 1918. five ships came up to the coast of norfolk, no bombs were dropped on land, but l7o, the latest word in airship construction, was destroyed. in the great aeroplane raid of may ro 1918, the germans made their maximum effort in this form of attack; between 30 and 40 gothas of the 3rd bombing squadron took part, with at least two giant machines. thirteen of the raiders managed to get over london. the casualties included 34 killed and 08 injured, and £130,000 worth of damage was done in the london area alone. but the defence had by now made very real progress. the germans lost 7 machines, 3 shot down in air combat, 3 destroyed by gunfire, and one from engine failure. this success of the defence was final, and the london area was saved from further bombing. in addition to casualties (1,413 killed, 3,407 injured) and dam- age, the german raids on england produced actual results by no means negligible. a night raid stopped munition work over a large area. in order to establish a defence, men and material were kept back from france: two hundred aeroplanes of the al r r al ds plate < : a” sales air raid defence one of the balloon aprons covering the approaches to london in 1917-18. the effect of these aprons was to limit the german bombers to certain heights, and to make it easier for the defending patrols to obtain contact. airscrew best performance and 200 highly trained pilots were available about london at a time when they would have been of the ut- most value on the western front. (e. b. a.) european air raids—apart from raids that formed part of the ordinary operations on the various battle fronts, there were raids on towns of france, germany and elsewhere, similar in intention to those on great britain. on sept. 27 1914 the first bombs were dropped on paris by a german aeroplane. on march 18 1915 bombs were dropped on calais, killing 7 french refugees and injuring twelve. on sept. 22 1915 french acroplanes dropped bombs on stuttgart as a reprisal for the bombardment of open towns by the germans. in dec. there were air raids on calais, and salonika was bombed by the germans. in 1916 on jan. 29 a zeppelin flew over paris, dropping bombs which killed and wounded over 50 persons. in feb. and march 1917 the germans raided salonika, and in april 1917 a large squadron of british and french aeroplanes bombarded yreiburg as a reprisal for attacks on british hospital ships. during the autumn of 1917 the british and french repeatedly carried out raids on the towns of western germany, and in particular on saarbriicken and kaiserslautern. on dec. 24 1917 a british squadron dropped a ton of bombs on mannheim-on- the- rhine. early in 1918 the british and french flying corps carried out raids against the towns of western germany. one of the most successful of these was on jan. 14 by the british upon karlsruhe, when the main railway station was heavily bombarded and many buildings set on fire. on march 11 1918 hostile aeroplanes raided paris. on march 29 1918 good friday, a shell from “ big bertha ” hit the church of st. gervais, killing and injuring many of the worshippers. in may of the same year british airmen ‘dropped 33 bombs on cologne in daylight and also bombed the port of durazzo in albania and sank an austrian torpedo boat. on july r9 1918 british seaplanes bombed the zeppelin sheds at tondern (schleswig) and did much damage. birnliography.—n. pemberton-billing, azy war (1916); j. ella- cott, bombing squadrons: from the air (1919); air ministry, synopsis of british air effort during the war (1919); e. c. middleton, the great war tn the air (1920); the council and the war (london county council, 1920). airscrew.—the purpose of the airscrew (popularly known as the propeller) in an aeroplane is to transform the power of the engine into a thrust giving a velocity to the aircraft. it consists, usually of two, but sometimes of three or four, blades which have a length about five or six times their width and cross sections of aerofoil shape. one end of each blade is fitted to, or is integral with, a central boss, which fits on and revolves with a shaft of the engine. the blades are equally spaced round the boss. the motion of any point in the blade is made up of two mo- tions, the first (represented by a b, fig. 1) in a circle around the thrust life relative wind velocity a 6 fic. 1.—blade of an airscrew (see text). axis of the engine shaft, and the second the forward speed (b c) of the aircraft which the screw is propelling. this second motion is at right angles to the first. the resultant direction of motion is thus a c at an angle to the plane in which the screw rotates. since the forward motion b c is the same for all points in the blade whilst the circular motion varies from zero at the centre to ri. a maximum at the tip of the blade, this angle varies with the radius. each portion of the blade is set at a small angle to its resultant direction of motion. hence the blade is a portion of an approx- imately helical surface, the pitch of which is known as the geo- metrical pitch of the screw. each portion of the blade is exactly similar to a portion of an aeroplane wing. like the latter it experiences a “ lift ” tending to push the blade at right angles to the resultant direction of motion and a “drag” against that direction. the difference between the components of these forces in the direction of travel of the aircraft is the thrust, and the sum of the components in the plane of rotation of the screw is the torque against which the engine drives. in general the thrust is greatest when there is no forward motion of the aircraft. as the speed of the air- craft increases, the thrust falls until at a certain speed it becomes zero. further increase of speed would result in a resistance in- stead of a thrust. the distance travelled forward during one complete revolution of the screw when the thrust is zero is known as the experimental mean pitch. if t is the thrust, q the torque, n the rate of rotation in revo- lutions per unit time, d the diameter, p the density of the air in units of mass, then it can be shown that for geometrically similar airscrews t=p k, d‘n? o=p: kg dr k, and k, are numerical coefficients whose values depend on the ratio of the speed of translation and the peripheral speed of the tips of the airscrew. these coefficients can be experimentally determined on models of airscrews running in wind tunnels or they may be estimated. the methods by which such estimates are made and the theories on which they are based form the subject matter of much mathematical and experimental research, of which the following is necessarily a very brief outline. the bibliographical addenda gives references to the more important contributions. the montentum.—airscrew theory has developed along two inde- pendent lines. the first is the momentum theory and is associated with the names of froude and rankine. according to this theory the airscrew is assumed to be a disc moving at velocity v and im- parting a steady change of pressure to the column of air through which it moves. the thrust or change of pressure is necessarily associated with a backward velocity of the column of air which at some distance behind the disc will have acquired a velocity v which velocity is termed the “‘ outflow.”’ a part of this velocity \\ v is acquired in front of the disc and this part is termed the “ inflow \"’ and the factor a is called the inflow factor. the velocity of air passing through the disc is thus v+-av and the mass of air is a p (v-+av) where a is the area of the disc and p the density of the air in mass units. the thrust is estimated from the rate of change of momentum thus generated and is equal, therefore, toapv(v-+av). in the further development of the theory it is shown that the inflow is one-half the outflow velocity, ¢#.¢., \\=0-5, and thus t= apv (v+4v), and also that the efficiency is v/(v+v/2). the velocity v is assumed as a purely axial outflow. in the actual air- screw the creation of a thrust is accomplished by the blade exerting a torque, which sets up a rotation in the outflow, and in a complete solution it is therefore necessary to consider a rotational inflow and outflow, | blade element theory.—the second line of development was pro- posed by froude and developed by drzewiecki and lanchester. in this—the blade element vheory—the blade elements are re- garded as aerofoils. the velocity of the air relative to the blade element is determined. from this the angle of incidence and the lift and drag forces follow. from these the thrust and torque of the elements are deduced and integration over the length of the blade gives the total thrust and torque. in the simple theory as developed by drzewiecki no account was taken of the inflow and in its applica- tion by designers the lift and drag forces of the elementary acrofoils were taken from wind tunnel tests of rectangular aerofoils having a ratio of length to width of about 6. it was further assumed that the clementary lengths behaved as if independent of neighbouring acrofoils, an assumption shown by recent work to correspond closely with fact. both these two theories are incomplete. the momentum theory takes no account of the turbulent and rotational effects implicit in the blacle element theory, which in most airscrews account for a very large proportion of the wasted energy. the second takes no account of the inflow shown by the momentum theory. 74 modified theories —efforts are therefore made, notably by fage, bothezat, riach and bairstow, to combine the two theories. bothe- zat and riach develop closely similar lines of argument. both take account of axial and rotational inflow and show theoretically that both are one-half of the additional velocity in the ultimate slip- stream. it is not clear what aerofoil characteristics are to be used. if characteristics taken from wind tunnel experiments are usec, the theories appear inapplicable for practical design, since the angles of incidence quoted in such experiments are not the angles to the rela- tive air at the acrofoil but to the air unaffected by its action. fage avoids this ambiguity by using an inflow factor which is frankly empirical and is chosen to obtain agreement between the observed and calculated characteristics of the airscrew. a good exposition of the application of the inflow and blade clement theories to design is given by bairstow who uses an inflow factor of 0-35. glauert’s theory—probably the most complete and successful airscrew theory has recently been proposed by h. glauert in an aerodynamic theory of ihe airscrew. glauert has reviewed the whole basis of airscrew theory in the light of the circulation and vortex theory of aerofoils developed by prandt] and other writers. the theory is based in part on the conception of the slipstream as a cylinder of vorticity, and the relationship between the interference flow at the airscrew and the slipstream velocity is established in a manner more rigorous than that used by other authors. it is shown that it is not strictly correct to equate the thrust to the rate of change of momentum but that the difference is of no practical importance. when this point is neglected the solu- tion given is identical in form with that given by bairstow and in current use by designers. the essential feature of this theory in which it differs from or amplifies carlicr theories is that the aerofoil characteristics used should be those of an aerofoil having infinite length compared with its width. these characteristics can be deduced from those measured on aerofoils having a finite length to width ratio. the form of the correction follows from prandtl’s work and is given in a simple and suitable form by glauert. with such acrofoil characteristics the theoretical inilow factor of one half is used. this relatively new point of view avoids the empiricism of fage and bairstow and the uncertainties expressed as regards bothezat and riach and brings theory and experiment into close agreement. the theory does not attempt to take into account the effect of the periodicity of flow inherent in an air- screw which usually has two, and rarely more than four, blades. the author justifies his omission on the grounds of the good agreement shown between observed results and those calculated from his theory but it is this omission which leaves his solution still incomplete and which may therefore give rise to further developments. atrscrew windmills —the term airscrew has so far been used as applying to the only type of propeller used on aircraft. the term applies also to what is popularly known as a windmill. the function and working conditions of the airscrew windmill are in general the reverse of those of the airscrew propeller. the latter reccives its power as a rotating torque and transforms it into a moving thrust. the former receives power by means of a thrust duc to a forced translational velocity through the air and transforms it into a rotat- ing torque. the propeller accelcraics and the windmill retards the air passing through the disc of rotation. the various airscrew theories are as vali! for windmills as tor propellers, the windmill being regarded as an airscrew propeller with a negative velocity of advance. between the two states, however, there is a range of working, including that referred to by bothezat as the vortex ring state, for which the usual equations are inapplicable. there is room, therefore, for development in airscrew theory to cover this gap and to give a complcte solution for the thrust and torque of an airscrew under all possible conditions. work in this direction is proceeding in great britain. variable piich airscrews—when the normal aircraft engine is fitted with an airscrew of fixed pitch designed to allow it to run at normal rate of rotation at maximum flying speed, then at any less speed, the rate of rotation will fall until when stationary on the ground the rate of rotation is, according to circumstances, from 80-90% of the normal. thus it is not possible when taking off or climbing to utilise the full power of the engine. the speed of the engine also falls with increasing altitude, but only due to the decreasing speed of the aircraft, carburation, and airscrew frictional losses in the engine. apart from the effect of the last two points, it is correct to say that at any given aircraft speed the rate of rotation 1s independent of the altitude of flight, since beth the resistance of the airscrew to rotation and the power available to rotate it vary with the density of the air. if the engine 1s supercharged partially or fully to maintain its power independent of altitude, then this balance is destroyed and such an engine fitted with an airscrew of fixed pitch designed, say, to run at normal rate of rotation at a high altitude, would run much slower at lower altitudes thus preventing the utilisation of the full power of the engine under all conditions. in order to control the rate of rotation under all conditions of speed and altitude and to utilise the maximum powcr in the most efficient manner, it would be necessary to vary both the pitch and the diameter of the airscrew. the design of such a screw presents almost insurmountable difficulties and has not been seri- ously considered. although it does not give the most efficient screw for all con- ditions, an airscrew of which the pitch only can be varied is con- sidered a practical compromise. even this presents difliculties and at the time of writing a completely satisfactory solution of the problem has not appeared. in most countries promising designs are under experiment and the problem may be said to be well on its way toe solution. a variable pitch propeller is essential to the full success of the supercharged engine, but its advantages for the ordinary engine are very limited. lhe ifclicopter—the helicopter is a particular use of an air- screw. it has frequently been proposed and many attempts have been made to build an aireraft in which the direct lift is supplied by the thrust of an airscrew mounted in a morc or less horizontal plane, this airscrew replacing the conventional wings and air- screw. the advantages claimed are a vertical ascent andl descent. it is generally believed that the difficulties to be overcome are considerably greater than those presented in the conventional acroplane and that the resulting performance woukl be dis- tinctly inferior. the theoretical considerations have been dealt with by von karman and riach, the autogiro—whilst a successful solution of the helicopter is still wanting, a tvpe of aeroplane bearing some resemblance to a helicopter has been developed in spain by sefior juan de la cierva and deserves mention as being the first and only successful fundamental departure from the conventional type of acroplane, anil also as giving rise to new aspects of airscrew theory. this air- craft to which has been given the name * autogiro ” is an or- dinary acroplane with its wings replaced by four wings or blades rotating about a vertical shaft fixed at the cenire of gravity of the machine. these four wings constitute in effect an airscrew of large diameter. instead of this airscrew being driven by a power unit as in the helicopter, it is free to rotate and does so under the natural air reactions experienced by the blades when the airscrew moves through the air. it isin fact a windmill driven by a wind at small angles to the plane of rotation. the individual blades are hinged at their inner ends, so that they set themselves in a position in which the resultant of the lift and the centrifugal force passes through the axis of the hinge. the blades therefore rise and fall as they pass up wind and down wind re- spectively in one revolution. the efiective angie of incidence to the rclative wind varies therefore throughout a revolution. the net result is that the lift is concentrated at the centre of gravity of the machine without causing the rolling movement involved with a rigid airscrew. this particular and interesting application of the airscrew-windmill gives rise to new problems which are being closely investigated in great britain. bibliograpiy.—w. j. m. rankine in the transactions of the institute of naval architects (1865); s. drzewiecki, les coniptes rendus de pv academie des sciences (1892 and 1909); le bulletin de association technique maritime (1892, i900, i90i, 1910); ria- bouschinsky, budlettn du laboratoire aerodynamique de koutchino (1909 and 1912); l. prandtl, 7landwerterbuch der naturwissenschaft- en (1913); a. betz, zettschrift fur flugtechnik und motorluftschif- fahri (1915, 1920, 1924); l. prandtl, nachrichten der keniglichen gesellschaft der naturwissenschaften 2u gottingen (1918-9); a. betz, ibid., (1919); m. a. s. riach, ‘ helicopters,”’ aircraft engineering (1920); th. v. karman, “ helicopters,” zeztschrift fiir flugtechnik airship und motorlufischiffahrt (1921); th. bienen and th. v. karman, zeitschrift des vwereines deutscher ingenieure (dec. 20 1924); g. ea nouvelles recherches sur la resistance de lair de l’aviation igt4). ae the more important english work see reports of the aeronau- tical research committee, 1910-24. these reports include the works referred to h. glauert and a. fage. for the more importiunt american work see reports of the advisory committee for aeronautics cena which include g. de bothezat’s work in report no. 97 {i9q2t}. cathe te r. soreau,'2’helice propulsive (1911); c. dornier, berechnung der luftschrauben (1912); p. bejeuhr, luftschranben (1912); s. drzewiecki, theorie geuerale de uitelice (1920); l. bair- stow, applied aerodynamics (1920); a. fage, airscrews in theory and uae (1920); h. c. watts, screw propellers for aircraft (1920). a bibliography of modern theory and research will be found at the end of a. fage’s text-book. apart from the text-books which are included for convenience, only authors and papers are mentioned which are considered 10 con- tain fundamentally new developments; papers of purely expository value are omitted. for detailed references see ‘‘ propellers ”’ in the smithsonian bibliography of aeronautics, vol. 1 (to 1908), vol. 2 (1909-16), vol. 3 (1917-9), vol. 4 (1920-1), vol. 5 (1922). (ch. ce wo) airship (sce 1.260)—three generally accepted types of airship—non-rigid, semi-rigid and rigid—have been evolved. ach in its own particular way aims at providing a container or envelope which will mect all the conditions described below, and hitherto each type has had its structural limitation which has prevented the choice of an absolutely ideal shape. in the non-rigid and semi-rigid types, the variation of gas volume is dealt with by providing internal ballonets which are inflated with air, from a blower or scoop or valve in the nose of the ship. they swell up or deflate within the gas space, thus maintaining in the main envelope which contains the gas a constant but verv small excess of pressure above that of the atmosphere. this small excess pressure with the aid of the tensile strength of the. fabric serves to preserve the form of the flexible envelope against the distorting forces due to various conditions of static and dynamic loading. non-rigid type—the non-rigid type has an envelope of rubber-proofed fabric from which one or more cars are slung by wire rigging while the stabilising and controlling planes are sup- ported on skids directly attached to the envelope. the chief classes of non-rigid airships are:— (1) those with a plain envelope of circular cross section, from which the cars, etc., are suspended from special patches on the envelope. this class is exemplified in the british s.s. and small american ships. : ; (2) the german parsival type, in which an envelope of circular cross section is reinforced against bending under the rigging tension by special trajectory bands disposed along lines of greatest tension in the surface of the envelope and terminating in a girdle to which the car is rigged. as (3) the french astra torres type, trilobe in section, with riggings led inside the envelope and divided into fans secured to points along the two top ridges. this type was developed in england during the war, and is represented in the n.s. class. the non-rigid type was developed most successfully in ger- many and france before the war, in england during the war, and latterly in the united states. it has the merit of great simplicity, and has been most successful in small sizes, say from t,0co to 10,000 cu. metres capacity, or from 1 to ro tons gross lift. the application of these small airships is for such purposes as coastal patrol, where ability to tly for long periods at moderate speeds is required, or for patrol or inspection at low altitudes over tracts of country unsuitable for aeroplane landing grounds. they have been successfully operated from temporary bases constituted merely by a clearing in a wood with a narrow avenue leading to open ground, this shelter proving sufficient in winds of 60 m. per hour. semt-rigid type-——the semi-rigid type has been developed chiefly in italy. a fabric envelope divided into compartments is employed, stiffened longitudinally by a framework, usually of steel tubular construction, running along the bottom and rigidly connected to the stabilising fins at the after end. it is claimed that a given weight of metal can be more economically fie disposed in the form of a frame of fewer members carrying greater loads than in the form of an exceedingly slender frame completely outlining the hull such as is involved in a small rigid . airship. on the other hand, particularly when mast mooring is contemplated, there is a tendency in the larger ships to extend the structure at nose and tail, and to widen the keel structure, so that the distinction between the types becomes less marked. the range of size for which the semi-rigid type is appropriate, and particularly its upper limit, can, as yet, only be a matter of personal opinion. a ship of about 50 tons gross lift is at present being built in italy, and will be the largest vet built of the type. the best existing semi-rigid airship is probably the italian “ n1,” particulars of the performance of which are given in the table. in these two ships the arrangement of accommodation, power cars, fuel storage, etc., is similar to that of modern rigid airships. the “ nr” and the zeppelin rigid ‘“‘ bodensee ”’ are of similar size and similar in performance. these two ships are good repre- sentatives of their respective types for this particular size. rigid type.—lit is, however, in the large, rigid type that the unique possibilities of the airship are fully realised. develop- ment of the rigid airship is largely the outcome of persistent eflort, aided by the state, by the zeppelin and schiitte-lanz companies in germany. their results have been carefully stud- ied by other nations, active interest being taken principally by great britain and the united states. great britain built one rigid airship in 1909, and in this and others built during the early part of the world war achieved a measure of success independent of germany and with little knowledge of her methods. in the latter part of the war details of german design became available, and full advantage of this was taken in british ships built sub- sequently. there are two assets of the airship which distinguish it essen- tially from heavier-than-air craft, and may be expected to ensure its continued development. for the first, fundamental principles indicate that as size is progressively increased, range and/or speed will also steadily increase, while they do not indicate any well-defined limit to such increase in size with known materials. consequently, larger airships than have yet been built will undoubtedly give greater ranges and speeds than those hitherto realised, quite apart from improvement to be expecied in design and metallurgical science. the second is the ability to remain aloft independent of motive power. developmenis—although the development of the airship com- menced many years before that of the aeroplane, it has never been pursued with anything approaching the intensity applied to the latter. consistent development over extended periods has taken place in only two countries, germany and italy. more recently great britain, and, to a smaller extent, the united states have contributed substantially to the sum total of progress. france took a leading part at first, but has done little in the last decacle. the small share of aeronautical effort devoted to the airship as compared with the aeroplane, is no doubt largely attributable to the relative size of individual craft of the two classes, which greatly affects the relative cost of each step in development although having no direct bearing on the cost of operation of serviceable craft. the aeroplane, promising so much, has pro- vided since its advent an almost sufficient scope for available talent. in consequence, the airship has not hitherto realised expectations based upon current engineering knowledge to the same degree as craft heavier than air. lifting power.—an airship derives its static lifting power from the fact that its gross weight is less than the weight of the effective volume of air which it displaces. a large envelope or container, to have a gross weight less than that of this volume of air, must be filled with some very light gas, or its internal space must be vacuous. the latter alternative has not been found possible, since the weight of the walls of the container would have to be very heavy to resist the large difference of pressure which would exist between the outside and the inside. the only suitable gases which exist for the inflation of an airship, in order to give it a reasonable amount of lift, are hydrogen and helium. 76 the gross lifting force of an airship is equal to the product of the volume occupied by the gas, and the difference between the densities of the surrounding air and of the gas. the density of pure hydrogen is 7% of that of air at the same temperature and pressure. similarly the density of helium is 14% of that of air. consequently, some 7% of the gross lift obtainable with hydro- ecn is lost by exchanging hydrogen for helium. in recent air- ships filled with hydrogen, about 40% of the gross lift has been available for paving load and fuel together, and as the loss of lift on substituting helium must be borne by these two items, it can be represented as a reduction of each by (7x22) %, that is, by 173 %. neither gas can be obtained or maintained quite free from air in practice, and there is a loss of available lift on this account. the large size and necessarily light weight of the structure not only put the idea of a vacuous container out of court, but actually require that the pressure of the contained gas shall be practically equal to that of the surrounding atmosphere at all times. the temperature of the gas may, however, differ appreci- ably from that of the surrounding air under conditions referred! to below. regulation of volume.—since the volume of a given mass of gas when the pressure and temperature vary is proportional to the ratio of its absolute temperature to its pressure, provision must be made for change in volume of the gas within the envelope when these factors vary, notably with change of altitude. the gas does not fill the whole volume within the envelope and the required adjustment is invariably effected by admitting air to occupy the varying difference betwecn the volume required by the gas, and the total volume of the external envelope. mux- ture of this air with the gas is prevented by flexible separat- ing surfaces whose arrangement varies with individual design. a sufficient increase of altitude must clearly result in expansion of the gas bevond the bulk of the external envelope. gas ts then irrecoverably discharged through safety valves, leaving the envelope just full of gas when the ascent ceascs. during any variations of height below this limit the mass of contained gas remains constant. its pressure is always equal to that of the surrounding air, and its temperature approximately so. conse- quently, under these conditions the mass of displaced air and the lifting force also remain approximately constant, the only variation being clue to difference between the temperatures of the gas and surrounding atmosphere, and a small correction for humidity. the height at which the gas would just fill the enve- lope is known as the “ pressure height.”” an airship may alter its altitude below this limit substantially without change of lift; but must lose gas, and consequently hfting force, if it exceeds that height, and in this event will have, of course, a new “ pres- sure height.”? these considerations are essential for an appre- ciation of the conditions governing the flight of an airship, yet have been seriously misstated in more than one comparatively recent work, purporting to deal authoritatively with airships. temperature v ariations.—a dillerence in temperature between the gas and surrounding air often results from solar radta- tion, which heats up the gas just as the air in a greenhouse becomes heated. such a difference is known as superheating. the same or the reverse effect may also be produced, at least temporarily, when flying through atmosphere of varying tem- perature. again, when altitude is changed rapidly, so that the gas expands or contracts nearly adiabatically, its temperature may vary more rapidly than the usual atmospheric temperature gradient. the maximum lift obtainable at ground level by fill- ing the ship full of gas, thus renclering the ‘ pressure height ” zero, is governed by the density of the air at ground level, and therefore varies with barometric pressure and air temperature prevailing there. | an airship commences a long flight full, or nearly full, of gas, thus realising its maximum lift. the pressure height is small in consequence. as the flight proceeds, fuel is consumed and the ship acquires excess buoyancy. to maintain static equilibrium gas is deliberately discharged. it is not, however, necessary to airship preserve correct static equilibrium at every moment throughout flight, since a certain departure from static equilibrium is already countered aerodynamically, as explained below. the envelope will be subjected to the lifting forces due to the displacement of air by gas and the gravity forces due to the weight of structure, gas-bags, gondolas, machinery, fuel, etc. the aim in design is to balance these forces at every point along the ship, as nearly as possible. it will be obvious that this idea cannot be realised for every condition of loading, hence the envelope will be subjected to bending and shearing forces in a vertical plane due to what may be described as static causes. the envclope-—the envelope must be provided with stabilis- ing surfaces or fins which, in all modern airships, are attached to the stern. to these fins are attached hinged flaps. those on the horizontal fins serve to incline the axis of the ship to the horizontal plane. when thus inclined the envelope acts some- what in the same manner as the wing of an aeroplane, and in its passage through the air experiences an aerodynamic force urging it up or down, according to the direction of inclination. this is the normal method employed for alteration of altitude during flight. moreover, if there is any lack of static balance which it may be undesirable to correct by discharge of gas or ballast, then the ship may be flown with its axis inclined, and kept on a horizontal path by means of the acrodynamic up-thrust, or down thrust. (this force may be quite large. in the case of r33, which has a gross lift of about 60 tons, the maximum possible dynamic lift is about 5 tons, 7.e.,8°%.) this inclination, of course, reduces the forward speed. when the nose of the ship is inclined upwards, the general character of the distribution of the acrodynamic up-thrust is that of an upward force on the nose and tail of the ship, and a lesser downward force near the centre. it thus subjects the envclope to additional shearing and bending forces in the vertical plane. in a similar manner the flaps or rudders attached to the vertical fins serve for stecring the airship, 7.e., turning her in a horizontal plane. in such a manoeuvre, the centrifugal force on the airship, acting outwards from the centre of the turning circle is balanced by a large aerodynamic force acting inwards on the forward portion, a similar one acting inwards on the tail and fins, and a small one acting outwards about the centre. the envelope is thus subjected to bending and shearing forces in the horizontal plane also. the shape of the envelope should be such as to give the least possible resistance for its volume. the ideal appears to be a bluff nose with a curvature which decreases progressively toward the tail. the shape of the hull in early rigid airships was cylin- drical, with more or less pointed ends and a ratio of length to diameter of 10 to 1, or even greater. research on models in the wind tunnel has shown that a very much reducedl resistance to motion for a given volume is offered by a fair shape conforming to certain general principles and from about four to six diam- eters inlength. ‘this has been borne out in practice. the cylin- drical portion was progressively reduced and died hard on account of its cheaper construction, but it has disappeared completely in recent designs. the specific resistance does not vary much over the range of “ fineness ratio’ mentioned, and choice may be determined by considerations other than those of head resistance. at a value of seven, however, the resistance may be expected to show an appreciable increase. insufficient appreciation of the forces exerted by the air on the hull during various manocuvres was reflected in the historic disaster to r38, a british-built airship which broke into two parts in the air in 1921. this accident emphasized the need for more exact determination of the loads imposed on the structure under all conditions of flight, as also of the internal stresses resulting from these loads, and led to the carrying out in eng- land of research to fill the more important gaps in the fund of data necessary for precise design. the present airship programme of the british govt. includes extensive research into the distribution of acrodynamic forces and methods of determining internal stress distribution in struc- | tures such as that of rigid airship hulls. airships plate hed a > } . an » [ . 7 . | al ~ . ae f — | : peer f << ttm ese ieee ‘ \" = — - fic. t. british naval airship n.s.11. fic. 2. british airship r.33 with d.h.53 light monoplane attached. fic. 3. ‘leer of extanetint showing attaching mechanism. fic. 4. u.s. airship ‘* los angeles” in her shed at lakehurst, n.j. fic. 5. r.33 at mooring mast if 2 and 5. “central n f . “topical pr ) airship the iull.—the hull of a modern rigid airship is a stiff frame- work completely covered with fabric to provide a smooth exte- rior and it contains a number of fabric gas-bags, each free to expand or contract within the limits of its allotted space, within a wire network closing the panels in the structure, and trans- verse bulkheads, also of wire, which prevent axial movement when the ship is inclined. the atmosphere has free access to the interior of the hull through suitable openings in the outer cover to accommodate change of volume of the gas in the bags. some four, five or six propulsive units are attached below the hull, each consisting of a car containing an engine driving an airscrew, to which it is coupled either directly or through reduc- tion gearing. the several cars are so disposed that the slip- stream from the propeller of each does not interfere with that of any other. there is normally a mechanic on watch in each car, and minor repairs are possible during flight. fuel tanks are disposed within the lower portion of the hull, where accommodation for personnel is also provided. the ship is navigated from a car which nor- mally has the form of an excrescence on the under side of the hull. access to the exterior of the hull at the top and at the - stern is usually provided. zeppelin hull.—the zeppelin hull comprises a shell frame- work of duralumin lattice girders and steel wire bracing. the girders are built up of rolled sections and stamped lattice pieces, riveted together. main longitudinal girders run from bow to stern, with polygonal transverse frames at equal intervals. the latter are normally of two types, main and intermediate, placed alternately. of these, only the main frames are braced in their own plane by wires traversing the hull and constituting the bulkheads which locate the gas-bags axially. other builders have followed zeppelin practice latterly, but a departure is to be anticipated in future designs since types of girder more eco- nomical in weight are now known, and because increased sizes and loads will favour alternative arrangements of hull members. the gas-bags.—the gas-bags are of light cotton fabric, lined with gold-beater’s skin, for which a synthetic substitute suffi- ciently gas tight and of similar weight has not yet been found, although it is an object of research, and there is little doubt that one or more will be found. the engines.—petrol-burning engines are used; yet condi- tions of service differ sufficiently from those for which aeroplane engines have been developed to render the latter in general unsuited for airship use. in a large airship, the total engine . gas : total mics length, ae capacity, ie dispos- p feet feet | million | you% {able lift, cub, ft. tons non-rigid s.s.z. british, igl6 , . 143 30-7 0:07 2:15 0-7 n.s. ditto 262 54 0:37 ii-4 4:3 semi-rigid n.1.italian, 1924 . 348 60 0-67 20°3 8 mr. ditto 105 24 0:035 1-07 0-5 rigid r bodensee,”’ german (modified), 1919 . 430 61°5 0-8 24°3 10 r33, british, 1918 . 640 79 1-96 60 24 zr3, german, . 1924 . 656 go:5 2-48 ie 7/ power installed is comparatively small in relation to the gross weight; whilst the initial weight of fuel per horsepower installed, or, in other words, the number of hours flown at a stretch, is relatively great. an engine is therefore required which gives high fucl economy at a power output which it can develop for many hours continuously and consistently. a relatively heavier engine is justified to achieve this. the german maybach is the only notable example of an engine developed for airship use. reduction of hull resistance by improved design involves either reduced number or dimensions of propellers for equal results, or increased propeller efficiency for the same dimensions, irrespective of the power applied. these processes are mutually reactive, because the resistance and weight of the power units and propellers is such a large proportion of the whole. as a result, very great improvement in acrodynamic efficiency has been achieved with progress in design. incidentally the power installed has increased vastly, and direct coupling of engines to airscrews, which was at first out of the question, is now practicable with the advantage of simplicity. performance.—of the two chief assets of the airship cited earlicr, the small airship can claim only the second. but this gives a suflicient advantage over other types of aircraft for some purposes, and although the performance is relatively low, one factor may be made good at the expense of another. that is to say, if speed is not required, the craft may remain in the air for a long time, and cover a reasonable distance when employed for purposes such as those already mentioned with reference to non-rigid airships. the large airship has demonstrated its capacity for fast long- distance travel. zr3 flew without stop 5,000 m. at an effective speed of 60 knots with no paying load and little margin of fuel. this implies that a distance of the order of 2,000 m. would be economically well suited to this ship, allowing for roughly equal division of available lifting capacity between fuel and paying load (to give maximum ton-mileage) after providing a reserve of fuel for emergency. it may be remarked that the same argu- ment as to relation between extreme range possible and a commercially advantageous range applies equally to any power- driven aircraft. zr3 is of 2,500,000 cu. ft. capacity, or about 75 tons gross lift. the construction of airships of twice this size has now been embarked upon, and correspondingly enhanced performance is anticipated. the table gives some data for several types and sizes of ships. extreme range in : still air with no engines useful max. paying load at lift, speed, speeds specified tons - knots rani@eal ota wautica ‘ no. |p oe h. miles knots 750 at 43 0-43 i 80 80 a3 1,000 ua a a 1,200 ‘50 3:2 2 275 550 50 1.800 7 , 39 1,850 i: 5°5 3 245 735 59 { 4600 | oe 40 40 39 1,000 ‘30 1,900 65 7 4 240 960 65 { pees tt 40 15 5 250 1,250 523 if useful lift be divided equally between paying load and fuel, and one-third of the fucl be set aside for head w eon: and reserve for contingencies, ranges are reduced to one-third of the figures in the table. 78 the performance of an airship is adaptable to requirements. useful lift is defined (in england) as the total available for fuel and paying (or military) load together. it may be divided be- tween the two in any desired proportion. for reconnaissance of patrol, the whole of the useful lift is available for fuel. for commercial work, an equal division between fuel and paying load gives maximum ton-miles, and represents an ideal to be kept in view in choosing routes and intermediate stopping places. strength and rigidity of the structure in a particular design limit the horse-power which can be safely installed. if relatively low speeds only are required, useful lift may be increased by reducing the weight of machinery. altitude, at the commencement of a flight, is obtainable only by sacrificing useful lift, since the maximum lift will be deter- mined by the gas which can be contained at the desired pressure height, and is correspondingly less than that of the ship full of gas at ground level. high altitude may be a military require- ment. at 20,000 fit. the gross lift has roughly half the value available at sea-level. the actual power necessary to obtain a given speed, and the acrodynamic loads which may be applied to the structure at that speed, are similarly reduced. if, there- fore, full speed is only required at great height it is permissible to reduce the strength and weight of the hull, and advantageous to use a super-compressed, or better, a super-charged engine which will give the required power at the working altitude with reduced machinery weight. for commercial purposes, however, great heights are not sought. it is desirable to fly above the disturbed and “‘ bumpy ” air overland in daytime. more advan- tagcous winds may sometimes be found by changing altitude. a reasonable height under good conditions is 2,000 fect. at the latter height the maximum lift is, in an average atmosphere, about 6°% less than that available at ground level with a ship quite full of gas. as a first approximation, the range corresponding to a given quantity of fucl is inversely proportional to the square of the speed. that is to say, the range at half speed should be four times that at full speed. this relationship is modified by the following factors, in order of importance:— (1) winds have relatively less effect as speed is increased. (2) temporary departure from static equilibrium, compensated by inclined flight, causes relatively less increase in resistance at high speeds. (3) the overall efficiency of the propulsive machinery and air- screws falls off somewhat with decrease in speed. this effect depends considerably on design. economical speed.—were none of these factors operative, fabulous ranges would be obtained at very low speeds. all these factors, however, tend to increase the economical speed, or speed at which the range is a maximum for a given quantity of fuel, and either x or 2 may provide a definite lower limit to the speed. in passenger carrying it is essential to make such an average speed over the whole journey as will offer sufficient advantage over alternative means of transport, and unless the economic speed is of the same order it cannot be considered. generally speaking, the economical speed for a large modern airship under average conditions will lie between 25 and 40 knots, relative to the air, while a speed of the order of 60 knots is prob- ably required for passenger service in competition with other conveyance. for reconnaissance and patrol, however, 25 to 40 knots may be very suitable, and, owing to the enormous corresponding ranges, may make the airship a very useful craft for these duties. in estimating the fucl required for a certain journey with a particular airship it is clearly necessary to take into account :— (1) the average wind to be expected. (2) the speed at which it is intended to fly. (3) the degree of uncertainty as to the average wind, and the existence or otherwise of emergency bases as determining the reserve of fucl necessary as a.margin beyond estimated requirements. these considerations show that statements of range, carrying capacity and speed of airships, as of other aircraft, can be very misleading unless relevant conditions are specified and appre- ciated. atkship piloting and navigation.—the distance flown in one stage by a large modern airship is such that widely differing alternative routes can be taken without material increase of mileage. this permits prevailing winds to be avoided or taken advantage of to a valuable extent and similarly enables temporary adverse winds such as those accompanying cyclonic depressions to be wholly or partially avoided, when the affected area is advised by a meteorological service or appreciated fram observations on board. the careful selection of routes both before and during flight is of great importance in reducing the reserve of fuel nec- essary, and thereby increasing the useful load, as well as enhanc- ing the regularity with which a time schedule may be worked to. good meteorological information is essential to successful com- mercial airship operation. it is now available, and its scope is increasing apace. flight by night presents no difficulties, but rather the reverse, owing to the absence of superheating. a striking demonstration of this, and of the safety of airship travel, is the fact that it is not unusual to make the first trial flight of a new airship by night. 3 safety in flight depends upon the ability and judgment of the captain and the ability of the navigator rather than on manipu- lative skill. in determination of geographical position, all the usual methods are available, including astronomical observa- tion and radio direction-finding. the restrictions as to space, position of instruments and general convenience of the navigator, which necessarily obtain in present heavier-than-air craft, do not apply to the airship. changes in buovancy.—as has already been explained, changes in buoyancy occur during flight from various causes. that due to consumption of fucl is met by discharging gas. temporary changes of temperature either of the atmosphere or of the gas are constantly occurring during the daytime. fortu- nately, the vertical aerodynamic force available by flying in a slightly inclined attitude is sufficient to deal with these tempo- rary variations of buoyancy. the amount of inclination re- quired, and with it the relative increase in drag due to this inclination, vary inversely as the speed. this always tends to increase the economical speed of flight. at currents and storms—moderate vertical air currents are expericnced, usually in conjunction with changes of air tem- perature and particularly at moderate altitudes in hot countries. these are met in flight by inclining the ship and present no difficulty except when landing at noon or afternoon in places where such currents are prevalent. it is remarkable that such districts commonly provide particularly easy landing conditions at other times. vertical currents of a more serious kind occur in thunderstorms and “line squalls.” these can usually be avoided by the aid of visual or communicated warning. their vertical velocity may be greater than that which an airship could counter by inclination to maintain her altitude. also such currents may have sharply defined boundaries so that a ship would be involved and carried up or down before she could incline by means of the elevators. again the first action of the current or gust tends to incline the ship in a sense the reverse of that desired. it is therefore important that an airship should be able to sustain without damage a rapidly impressed change of height, and hence of atmospheric pressure, which may in extreme circumstances be unavoidable. that implies chiefly—adequate openings for air entering or leaving the hull, and adequate gas safety valves in case the ship should be driven above her pressure height. the provision of these is practicable. the conditions also provide one of the most severe cases of aerodynamic loading to be taken into account in designing the hull structure. fire risks—careful metallic bonding of every part of an airship is adopted, and has been proved to be necessary and effective in climinating the danger of ignition of hydrogen by electric spark. this bonding prevents difference of static elec- tric potential arising between various parts. cases of airships having been struck by lightning without harm are on record, a necessary precaution in these circumstances being to avoid discharge of gas. handling on ground and mooring.—a large airship cannot be air, the war in the taken into or out of a shed in more than a moderate wind if the wind direction be across the entrance. since there are compara- tively few favoured regions where light winds are the rule throughout the year, such a limitation on airship operation could not be accepted. a revolving shed has been built in ger- many, which could always be swung round into line with the wind, but this could not be considered a satisfactory solution owing to its high cost. the mooring mast.—these facts have led to the development of the mooring mast, to which the bow of a ship may be directly connected by a universally jointed coupling. having been the subject of isolated and inconclusive experiments at various times, including trials with the first british rigid airship in 1900, the mooring mast was proved as thoroughly practicable for large rigid airships by extensive trials made in england in 1920 with r33. it was then shown that an airship can remain at a mast in strong winds, and can moor in a wind of over 30 m. per hour. these figures do not represent limits, but the maxima that were attempted. the same airship, brought again into use in 1925 after several years of inactivity, broke away from the mast in a gale. loads are imposed on the forward portion of the hull by mast mooring, different from those which may occur in flight. r33 had not been designed for mast mooring, being an old ship impressed for the experiments of 1920, and had been equipped for these tests with a special bow cap. in the light of more recent knowledge it appears that the factor of safety con- ferred on the forward portion of the hull by this modification, was inadequate to deal with the lateral loads imposed on a moored airship by rapid change of velocity and direction of the wind such as may occur in stormy weather. the subsequent flight for 30 hours and eventual safe landing with an exten- sively damaged bow are famous, and provide evidence of the ability of an airship to proceed under control at reduced speed when seriously damaged. the mooring mast achieves much more than the ability to land and leave in other than fair weather. it enables this to be done with about ro men in place of a landing party of several hundred. it removes the necessity of going into the shed except as a sea-going ship goes into dry dock, since fuel and gas are piped up the mast and running repairs can be effected there. all this was demonstrated during the trials referred to, when r33 was continuously operated from the mast for several months without entering her shed. consequently, intermediate bases on a long route need a mast alone, the cost of sheds being saved. landing.—an airship landing to a mast drops a length of cable from her bow which is then coupled to a cable led out through the mast-head, enabling the ship to be hauled in by a power-driven winch. the chief technical difficulty which had to be overcome in developing the method was that of rendering the final stage of hauling-in, steady. the system devised for the 1920 trials with r33 has been adopted in america and used extensively for the airship “shenandoah.” ‘this airship was also successfully operated from a mooring mast erected on the steamship ‘‘ patoka.” small, non-rigid airships have also been adapte<| for mast mooring. one of the more successful experiments in this clirec- tion took the form of a mast having a rotatable horseshoe head, to which the ship was attached at a point on each side of the envelope a little aft of the bow. the need for mast mooring is, however, not so well established in the case of small, non-rigid airships, for which other methods, such as the natural shelter, referred to earlier, are available. aeroplane carrying.—the idea of an aeroplane being carried by an airship, flying from and returning to the latter at will, has long been in view as a means of combining the extreme mohil- ity of the one craft with the long range of the other. launching an acroplane from an airship in flight has been achieved success- fully on a number of occasions in the course of experiments con- ducted in several countries. in some tests in america an aero- plane made “ contact ” with an airship in such a way as to show that re-attachment was probably feasible although it was not actually performed. recently in england the complete process ae, has been carried out, a light aeroplane leaving the airship r33 in flight, being subsequently re-attached by its pilot, and properly made fast again to the airship. in this experiment the aero- plane returning to the ship attached itself to a trapeze suspended some distance below the airship. this was subsequently hauled up and the pilot of the aeroplane was able to leave his machine and enter the hull of the airship. fuiure development—the design and construction of two airships of 5,000,000 cu. ft. capacity, or about 150 tons gross lift, has been sanctioned by the british government. these ships are to be tried in operation between england and india via egypt, in an endeavour to carry the development of the large airship rapidly to a stage at which it can be shouldered by com- mercial enterprise. in connection with the scheme, a suitable shed is being erected in england and another in india with a mooring mast in proximity to each, and an intermediate mooring mast in egypt, which will divide the journey into two stages and enable the ship to take supplies of fucl and gas. the risk of fire in airships, apart from military incendiary action, has always been on account of petrol rather than hydro- gen, and the precaution now taken in bonding of all parts for electrical conductivity has practically eliminated the hydrogen risk, with the reservation as to military action, while the petrol danger has remained. for the two airships now being laid down, petrol has been abandoned as a fuel in favour of crucle oil and kerosene, which are to be tried in the two craft respectively, the design of special engines being involved. it is further intended to test two methods of effecting economy over the normal system of discharging gas during flight equiva- lent in lift to the weight of fuel consumed. one of these is the recovery of water condensed from the exhaust gases of the engines equal or nearly equal in weight to the fuel consumed. this would render the discharge of gas unnecessary. the other is the use of hydrogen as a subsidiary fuel in such proportion to kerosene as to maintain the ship in equilibrium as regards buoy- ancy. by thus reducing the consumption of the primary fuel, an in- creased paying load may be carried. both methods have already been demonstrated to be possible. water recovery was regularly performed on the united states airship, ‘‘ shenandoah,’ al- though with corresponding disadvantages in weight and head- resistance of apparatus, which further improvement should remove. the use of hydrogen as an auxiliary fuel has been proved on ground tests, and has been tried in the air in small airships, but not to conclusion. (see aeronautics; flying.) brplrogrrapiy.—g. h. scott, “the commercial aspect of airship transport,” proc. internat. air congress, london (1923); v. c. rich- mond, ‘‘ the hulls of rigid airships,’’ proc. internat. air congress, london (1923); g. h. scott and v. c. richmond, ‘ the effect of meteorological conditions on airships,” jour. roy. aero. soc. (march 1924); j. c. hunsaker, “' the strength of rigid airships,” jour. roy. aero. soc. (1924); b. m. jones, “ aerodynamical charac- teristics of the airship,” jour. roy. a ero. soc. (feb. 1924); r.t. glaze- brook, dictionary of applied physics. see also reports and memoran- da of the acronautical research committee. (v.c. r.; ff. m. r.) air, the war in the.—airships and aeroplanes, as dis- tinct from captive balloons, were first used in warfare by the italian army during the campaign against the turkish forces in tripoli in ro1r and 1912. with the exception of aerial combat, there being no enemy aircraft to encounter, most of the features of modern air warfare were introduced by the italian airmen. both aeroplanes and airships were used extensively for recon- naissance work; the turkish positions were frequently bombed by both types of aircraft, which in some cases received damage from rifle fire and from guns trained vertically by the simple expedient of placing them on the slopes of hillsides; and enemy troops were subjected to fire from aeroplanes armed with rifles and revolvers. extensive photographic reconnaissance flights were made by airships and the photographs obtained formed into a mosaic . from which a revised general staif map of the tripolitan area was prepared. the world war.—in the world war the first squadrons of the british royal flying corps flew from dover to france on aug. 13 1914. squadrons 2 and 4 were homogencously equipped with 80 b.e.2 type aeroplanes, but squadron 3 had both bleriot mono- planes and henri farman biplanes, while 5 used farman and avro biplanes. though the lewis gun had been tested in an aero- plane in 1913, the adoption of machine-guns had not been gen- eral, and indeed no provision was made for the arming of these early machines, bomb sights and bomb racks being also lacking. this was partly because their primary duty was held to be visual reconnaissance, and partly because of the narrow margin of lift available, which prohibited any addition to the load beyond the weight of the pilot and of petrol. thesame consideration prevented the carrying of cameras, but valuable work was done by the early _ reconnaissance flights, the first of which was made on aug. 19. on aug. 23 the reports of the massing of german troops jed directly to gen. french’s order for the retirement which saved the british army, and timely warning was given on sept. 4 of the commencement of von kluck’s attempted enveloping move- ment against the trench left, which led to the battle of the marne. the first approach to a fight in the air occurred on aug. 22 1914, when a german albatross machine appeared over the aero- drome at maubeuge and was chased by several british machines. two days later the first german machine to be brought down was forced to land by machines of squadron 2. it was consid- ered at that time that the most suitable type for aerial combats was the slow two-seater henri farman with propeller in the rear giving a free field of fire for the observer armed with a riile. before the end of 1914 it was, however, beginning to be recog- nised that the greater speed and manoeuvrability of the single- seater gave it advantages over the slower type. the french tried to get over the ditliculty of firing forward in the tractor type, with propeller in front, by fitting metal plates on the air- screw blades to deflect the bullets, but this was found to have an adverse effect on the efficiency of the aeroplane. when the _ lewis gun was adopted, the british fitted it on the top plane to fire either over, or at the side of, the tips of the airscrew blades, the trigger being operated by bowden wire from the pilot’s seat. the selection of the single-seater machine for fighting purposes necessitated the adoption of the principle, already familiar in the submarine service, of training the whole machine at the en- emy aircraft with a fixed gun, in place of the free rifle of earlier days, or the swivelling gun of the two-seater. the cessation of movement and settling down into trenches and a war of positions led to the development of aerial photog- raphy, in order that changes in the positions or sizes of enemy railheads, ammunition dumps and camps might be recorded. early attempts at co-operation with the artillery also began, generally with the aid of coloured signal lights fired by the aero- plane to indicate the fall of shell; but as early as sept. 15 1914 an experiment in the use of wireless telegraphy on active service was made, and on sept. 27 the r.f.c. headquarters wireless sec- tion was formed. aw fighting develops.—atr fighting and organised bombing raids developed in 1915. early in jan. the germans made several raids on dunkirk with a number of machines flying together, in place of the isolated attacks by individual machines which had hitherto been the practice. on jan. 22, for instance, 13 machines appeared and dropped bombs on the docks. during the battle of neuve chapelle in march rors, in addition to the routine work of reconnaissance and artillery co-operation, the royal flying corps interfered with the enemy’s movements by attacking such important points on his lines of communication as menin, courtrai and douai. during the battle of loos on sept. 25, co-operation with the artillery was considerably improved and a system of ‘ zone” calls introduced, by which the guns could be rapidly put on to “ fleeting ” targets. the co-ordination of aeroplane bombing attacks with army operations was also further developed during this battle and attacks were made on railway lines, trains and important jjunc- tions. early in march the r.f.c. had received the first batch of a newly designed aerial camera, from which greatly improved photographs resulted. in may the germans produced the iok- ker monoplane equipped with an interrupter gear which enabled air, the war in the the machine-gun to be fired through the revolving tractor screw blades, a device which took by surprise the allied air services, which for some time to come were to continue to rely mainly upon “ pusher ” machines for fighting. at the beginning of 1916 the uses to which british aeroplanes were being put were recon- naissance, artillery observation and bombing with b.e.2 ma- chines; and acrial fighting with vickers and f.e. two-seaters, and with d.it.2 single-seater “ pusher ” machines and the new bris- tol scout single-seater tractor biplane with a machine-gun firing over the airserew. the universal adoption of the tractor type for fighting was still awaiting the synchronised gear operated by the engine for firing through the airscrew, which appeared on the curiously named sopwith “ pup,” a high performance scout, in the summer of 1916. squadrons for the definite purpose of fighting in the air were organised and a regular patrol was kept up by each squadron over its own sector of the trenches to engage and drive back the enemy’s long-range reconnaissance and bomb- ing machines. | verdun and the somme.—during the battle of verdun, which opened on teb. 21 1916, the french introduced a new and suc- cessful form of air fighting in sending their own machines into german territory to seek out the enemy machines before they reached the lines. this to a large extent enabled their own reconnaissance and artillery machines to do their work undis- turbed. the germans replied to this by developing the “ circus ”’ system, never copied by the allies, of giving a recognised star pilot, or “ ace ” as the french called him, command of a special fighting squadron for which he chose his own pilots. the origi- nator of this system was the german pilot boelcke; another famous leader being von richthofen, whose ‘ circus ” would move to different parts of the line, where the needs of the mo- ment called for it, in an effort to obtain local air supremacy. the opening of the battle of the somme on july 1 1916 was sig- nalised by intensive british reconnaissance and bombing flights, as well as by attacks with small 20-lb. bombs and machine-guns on the front line troops, in the trenches and billets and on trans- port immediately behind the lines. the same battle was also the occasion of the introduction of “‘ contact patrol ’? work in an organised manner and on a large scale. ‘this consisted in locating units of allied forces, and keeping headquarters informed of the progress from hour to hour; reporting on the positions of the enemy, and in particular on movements of his reserves; trans- mitting messages signalled by the infantry from the ground to headquarters; and dropping ammunition and supplies to isolated bodies of troops. the year 1917, and indeed the remainder of the war period, was chiefly occupied in developing and bringing to perfection the diflerent operations in which aeroplanes had already been en- gaged. fighting in formation was developed until it became a highly scientific operation in which whole squadrons and even larger formations were frequently engaged. bombing raids were also carried out in formation on a large scale, both by “ day bombers ” operating from behind the lines upon reserve ammuni- tion dumps, railheads, concentration camps and similar objec- tives and by twin-engined “‘ night bombers ” working from bases on the coast and far in the rear of the front line upon munition works and industrial centres in the heart of the enemy country itself. raids of this nature had been carried out by the germans from 1915 onwards, but it was not until 1917 that the appearance of the large handley page machine made retaliation possible; a development which led to the formation of the independent air force on june 6 1918, for the definite purpose of bombing german munition centres. (see arr rarps.) | in dealing with the use of aircraft with the military forces dur- ing the world war, attention has been confined to operations on the western i'ront, because the work in other scenes of war was mainly on the same lines, except for such spectacular per- formances as the wiping out of the whole of the turkish vii. army on sept. 16 1918, when it was caught in a ravine and bombed to extinction by relays of british aeroplanes. nothing has, how- ever, been said of the growth of the kite balloon service, which developed from two naval sections that arrived in france in air warfare may 1901s, until at the end of the war there was a row of them along the whole line of trenches co-operating with the artillery, for which work they possessed the advantage of rendering pos- sible direct communication by telephone between the observer and the battery. operations by naval atrmen.—the first naval fying operation of the world war was a patrol by parseval airship iv. during the night aug. 5-6 of the approaches to the mouth of the thames. airships and aeroplanes patrolled the english channel during the crossing of the expeditionary force to france. for the remainder of 1914 the naval air service was chiefly engaged upon bombing operations with land machines from aerodromes on the coast of france upon the zeppelin sheds at cologne, diisseldorf, friedrichshafen and other points. the navy intro- duced the kite balloon to the british services and in march 1915 the first kite balloon section left for the dardanelles in the “ manica,” from which ship the balloon was used to good effect in spotting for the “ queen elizabeth ” and other battleships engaging the turkish batteries and ships. about the same time a programme of ‘s.s.” (submarine scout) airships, for use in patrolling the channel and approaches to the irish sea, was laid down. by the end of 1914 three sea- plane carriers were in commission in home waters, and shortly after the new year the “ ark royal,’ soon followed by the “ ben-my-chree,” left for the dardanelles. from the ‘‘ ben- my-chree ” were launched the seaplanes which made history in attacking and sinking surface vessels by torpedoes dropped from the air. all these vessels carried the seaplanes in their holds and hoisted them out over the side by derricks to start from the water. in july rors, seaplanes were used on the east coast of africa in spotting for the monitors engaged upon destroying the german light cruiser “‘ kenigsberg.”” on nov. 3 1915 a bristol scout aeroplane rose from the foredeck of the “‘ vindex ” and thus became the forerunner of the ship aeroplanes which were subsequently developed. the autumn of 1915 saw the production of the first “‘ coastal ”’ two-engined type airship, for anti-submarine operations from stations on the east coast. during 1916 aeroplanes of the naval air service were still employed in bombing aerodromes, coastal batteries, docks and also points of military importance, while in the mediterranean regular anti-submarine and reconnaissance patrols by seaplanes and airships were instituted. in 1917 the navy introduced the handley page bombing machine which made it possible to extend the range of bombing attacks. in home waters a more powerful airship, in the ‘‘ north sea ” class, was produced and still further increased the length of anti- submarine patrols, while airships and, to a less extent, seaplanes began to accompany for prolonged periods the convoys of mer- chantmen which were organised by the admiralty. progress was made in the development of large flying boats operating from yarmouth and felixstowe, which patrolled the southern part of the north sea for submarines and zeppelins. the principle of carrying aeroplanes in ordinary ships of the navy and flying them from platforms revolving with the gun turrets was intro- duced, while the torpedo-carrying scaplane was also very con- siderably devcloped during-this period. aircraft versus submarine—in 1918 the german submarine campaign reached its height and anti-submarine operations were intensified. airships accompanicd the scandinavian convoy on the greater part of its journey, while a practically constant super- vision was exercised by seaplanes, aeroplanes and airships over the “ east coast lane,” a narrow belt of water close to the shore to which merchant ships were required to keep for their own pro- tection in their passage up the coast. all the american convoys, both of transports and merchant ships, were regularly met at a clistance of some rso m. from the coast and escorted to port. aircraft were, perhaps, the most potent factor in combating the submarine menace in convoy work as in reconnaissance, in co-operation with surface vessels and direct attack. kite bal- loons were also installed on monitors, patrol boats and even battleships as an aid to the location of submarines. towards the end of the war the “ furious’ appeared in its si converted form as a scaplane carrier with a long flying deck on which aeroplanes could land as well as take off. an instance of the production of a special device for a specific purpose may be mentioned in the mounting of a sopwith “ camel ” aeroplane on a lighter, towed behind a destroyer, for the purpose of making a surprise attack on a patrolling zeppelin airship. at the date of the armistice the british airship service was on the point of pro- ducing rigid airships capable of accompanying the grand i'lect to sea as advance scouts, but the german navy emploved zeppelins for this purpose on many occasions and throughout the war maintained a patrol of the north sea which enabled them to receive carly warning of the movements of the british fleet. (see convoy.) bibliography.—‘‘ contact,” an sas outings (1917); masmejean, avions allemands (1917); bishop, it ee warfare (1918); j. t. b. mccudden, ie vears in the royal flys: corps (1918); m.f. von richthofen, the red air fighter (ranslatcd 1918); p. bewsher, green bails (1919); e. c. vivian and w. lock- wood marsh, a history of aeronautics (1919); “ p.i.x.,” the eects web (1919); m. baring, r.f.c. /7.@., 1914-1918 (1920); 1 tennant, in the clouds above baghdad (1920); l. wolmsley, fae and sport in fast africa (1920); sir walter raleigh, the war in the air (1922); j. morris, the german air raids in the great war, iql4-1018 (1925). (www. l. m.) air warfare.—this article, after an historical introduc- tion, deals with the strategy and tactics of air warfare. i. historical sketch reconnaissance was, probably, the only clearly defined duty of the british flying corps, during the retreat from mons, and on sept. 13 when artillery observation by wireless telegraphy and photography from the air were carried out on the aisne. at the battle of festubert in may 1o15 there took place the first definite attempt at contact patrol with the infantry; ma- chines were allotted for artillery observation; bombing attacks were made on enemy railways and headquarters; and patrols were organised to prevent enemy air reconnaissance. at the battle of loos, sept. 25 1915, the co-operation with artillery was extended to counter battery work, and long distance recon- naissance was done as well as tactical reconnaissance. the next development was due to the appearance of the german fokker. this was a type of aeroplane specially designed for fighting, which seriously interfered with british artillery observation machines; and the practice began of allotting a fighter to an artillery machine for its protection. later a defi- nite offensive policy was adopted, and specialised fighting squadrons were organised. aircraft on the somme.—the next milestone was the battle of the somme in july 1916. aerial activity on this occasion in- cluded attacks on hostile balloons, railways and infantry in trenches; artillery observation and contact patrols with the in- funtry were carried out. in subsequent battles, as at arras, messines and the third battle of ypres, offensive patrols worked far over the german lines and even waited over their aero- dromes, their object being to ensure for the attacking infantry freedom from observation and for the artillery observation ma- chines freedom from aerial attack. there was consideralile bombing of railheads, trains, dumps and living quarters, both by day and night, and the use of photography was greaily extended. the battle that began on march 21 1918 marked an impor- tant change in air strategy. the normal search for information and the normal fighting for the maintenance of air superiority were completely abandoned in favour of intervention in the ground fighting. throughout the allied advance in the second half of 1918 the fighting in the upper air and the attacking of enemy aerodromes with bomb and machine-gun were resumed, as were also reconnaissance and artillery co-operation. further, there was a great increase in the attacks on troops on the ground, on bridges and on railway stations. co-operation «with the navy—the development of naval co- operation can most conveniently be considered under the headings of work with the battle fleet, commerce protection and the support of military expeditions overseas, respectively. 82 on the outbreak of the war several cross-channel steamers were bought and fitted up as seaplane carriers, to work with the harwich force; and a cunard liner was similarly used in the grand fleet. the next step in the evolution of the aircraft- carrier was the provision of ships with a flying deck forward whence aeroplanes could fly off, though they were forced to alight in the sea on their return. it was also found practicable to fly an aeroplane off a ship’s turret. finally, as the possibility of an aeroplane alighting on a deck became evident, aircraft- carriers were provided with a deck both for alighting and flying off. at the time of the armistice there were two large aeroplane- carriers, “‘ furious’ and “ argus,”’ the former carrying recon- naissance machines and the latter torpedo machines. in most light cruisers a single-seater fighter was carried, whose primary function was to attack zeppelins. each capital ship carried two aeroplanes cither single-seater fighters or two-seaters, the former to obtain local air superiority, the latter to spot for gunfire. during the last two years of the war long reconnaissance flights, of about 400 m., were made by flying boats from killing- holme, yarmouth and felixstowe, over the southern part of the north sea. the germans made no attempt to develop acro- planes or seaplanes for fleet work, but relied on their long range airships, which accompanied the german fleet on nearly all its important operations, and also maintained throughout the war a very effective patrol of the heligoland bight. in commerce protection aircraft played an important part. a bombing force was used to attack the submarine bases in bel- gium, and a limited amount of bombing of the submarine base at cattaro was done in the spring of 1917, but the most effective role of aircraft in anti-submarine warfare was convoy work. air stations were built up first of all in the english channel and on the east coast, and later they were extended to the irish sea, mediterranean, french coast, newfoundland and the gulf of st. lawrence. airships, {lying boats, seaplanes, aeroplanes and kite balloons were all used. in connection with the navy’s function of supporting mili- tary expeclitions overseas, the dunkirk aircraft kept a very close watch on the enemy’s belgian ports, to prevent his making, by surprise, a raid in force on the cross-channel communications of the british army. at the dardanelles aircraft co-operated with the ships, working both from carriers and shore bases. it was here that the first successful attacks by torpedo planes were made in aug. 1915. air co-operation was also provided for by the navy in east africa in 1915, in the red sea in 1916, in north russia and on the caspian in rg19. since the armistice con- siderable progress has been made in fleet co-operation, spotting for gunfire, reconnaissance and torpedo plane work, while the development of flying boats has proceeded so that they aze now capable of making cruises lasting several days. il. strategy and tactics the principles governing the strategy and tactics of air war- fare can now be reviewed, and when possible, suggestions can be made how such warfare may in future develop. armies of the air force.—l{ small wars are fought by the air force alone, the objective is to make the enemy’s life so burden- some—by material loss, by the interruption to normal life, by the moral effect—that he will sue for peace. this method of war is advantageous in that it can be used very quickly, and that provided the air base is secure, there is no line of communication to guard. moreover, the force can be kept centralised, which is both safe and economical. however, it is often necessary to employ troops also and in this case, the first dutics of the air forces may consist of direct action before the troops are in con- tact; then, normal co-operation with ground columns as they advance. in addition, there will be the work of watching the long line of communication, and of supplementing it by using aircraft for carrying men and supplies, and for intercommunica- tion. before ever force is resorted to, aeroplanes may, by demon- stration or dropping propaganda over disaffected areas, prevent the spread of trouble and render further action unnecessary. so air warfare successful and economical have these methods proved, that it is likely they will be considerably used in future for the control of semi-civilised areas. in a war to be won primarily by air action, the objective will be the same as in the small war, viz., to interrupt an enemy’s national life to such an extent that he prefers to make peace. an air force differs from a tleet or an army in that it cannot adopt temporarily the defensive, and then assume the offensive at its selected time, the reason being that it is impracticable to provide an air force with an impregnable base wherein to shelter during its defensive. therefore an air force must always be on the offensive, even if it is co-operating with a navy or an army which is temporarily on the defensive. air fighting is subject to the same principle. on the defensive it is difficult to avoid sur- prise, because attack may come from any direction or angle in three dimensions. the effect of the offensive on morale is prob- ably even more marked in air fighting than in sea or land fight- ing. one of the most important parts of any home defence organisation will be its offensive bombing squadrons. lactics of air fighting. —in a fighting machine the offensive is generally pursucd by means of surprise. in the case of one single-seater attacking another, surprise is obtained by attacking from above and behind, since the attacked pilot does not see in this direction. but where a two-seater is attacked, other methods must be used. for instance, attack may be made from behind clouds or from such a direction that the pilot and observer attacked cannot avoid looking towards the sun; or the enemy may be induced to attack a decoy aeroplane, whereupon he himself becomes attacked from above. fighting machines at first worked singly, later, the formations of fighters were adopt- ed, the most usual being a v echeloned in height. in the latter stages of the world war it became the practice for a fighter squadron to fly in three v’s, the leading v being the lowest, and the rearmost v the highest. thus the rear of a lower formation was guarded by the formation above it; in the same way that the rear of a single-seater fighter in a formation is guarded by the machine above and behind it. the attacks by fighters led to bombers in the world war flying in formation for mutual protection. a v formation was gencrallvy used. owing to the difficulty of attacking a well handled formation of bomb- ers, the practice of sending fighters as a close escort to bombers is to be deprecated as wasteful. moreover, fighters which are tied to a bombing formation necessarily lose much of their greatest asset, mobility. naval war.—lf a naval battle is fought outside the radius of action of shore-based aircraft the first air objective should be to obtain local air superiority, either by incapacitating the enemy’s carriers before their aircraft have taken off, or by air fighting. lf a fleet were to pass within the range of a powerful, shore- based enemy air force it would jose all power to effect surprise. another problem is the ability of an air force to drive an enemy fleet to sea in order that it may there be defeated. if the enemy’s fleet 1s based outside the range of shore-based aircraft, the limited effect of air raids by the machines from carriers would not suffice to do this, but if it is based within such range a reason- able measure of air superiority can be obtained, then by con- tinuous air bombardment the flect’s base could be made un- tenable. similarly, a smaller air force, though unable to main- tain an offensive strong enough to drive out the fleet, could watch the base so closely that if the fleet did come out, the fact would be quickly reported. tor the defence of trade outside the radius of shore-based air- craft, each ship would have to carry an aeroplane, if the trade were dispersed. a catapult or flying-off deck would be necessary and some device to enable the aeroplane to alight on the ship. if the trade were in convoy, it might be desirable to have an alrcraft-carrier with the convoy. within the radius of shore- based aircraft, trade could be assisted and protected by patrols from coastal stations, as in the world war, but to a greater degree in view of the increasing efficiency of aircraft. in attack- ing trade, aircraft could be most effective if directed against enemy ports, where trade would be concentrated, and the loading akhenaten—alabama and unloading of ships would suffer interruption. at sea air- craft, outside the radius of shore-based aircraft, could be carried in and used as auxiliaries by surface raiders or submarines. within the radius of shore-based aircraft, merchant shipping could be attacked easily and effectively. as all arms now use aircraft for tactical co-operation, it is to be expected that simpler methods of inter-communication will be evolved. again, as aircraft grow more powerful, the blows that are dealt from the air to the ground by bombing and shoot- ing will become heavier. bombing will become more accurate, and the increased range of aircraft will naturally give them greater scope. finally, the appreciation of the offensive power of air forces will probably lead to a greater use of air power at critical times, as, for instance, to fight a rearguard action or, conversely, to turn an encmy’s retreat into a rout. defence against overseas invaston.—in these operations air power appears to be of the greatest importance. surprise for a sea-borne land attack would be almost impossible to obtain in the face of aerial coast patrols. the patrols would give warning and the defenders would concentrate their sea, land and air forces at the point on which the attack was seen to be directed. one is led to expect an extension of this method of defence, which is obviously more economical than fixed defences distributed along a coast line. an adequate air patrol is essential. the great power of the defendcr’s aircraft to delay or stop an attack by damaging transports, by attacking troops going ashore or by preventing supplies being sent ashore after the troops are also to be considered. air power seems likely to favour the defender much more than the attacker. imperial defence —as regards the future use of air forces for empire defence it should be assumed that an air striking force ts normally stationed in some central position, whence air routes radiate to different parts of the empire, and that every outlying part of the empire that is liable to attack has a small garrison capable of holding out until the air striking force arrives. the arrival of the striking force would mean that the attacker would be unable to get that measure of air superiority which is essential nowadays for the success of any war by sea, land or air. one advantage of this strategy would be that the air striking force would arrive in a few days, whereas in the past, relief forces have taken weeks or months to reach their destination. another advantage would be its comparative cheapness, for the striking force would be centralised, which always makes for economy, and the air routes would be maintained by commercial aviation. the underlying strategic principle 1s that full use is made of the mobility of air forces to bring about a rapid concentration at the decisive point. (see british empire: defence.) (c. ry by) akhenaten.—akhenaten, the son of his predecessor amen- ophis iii. and his wife ty, came to the throne of egypt about 1375 b.c. not later than his sixth year the new king transferred his capital from thebes to tell el-amarnah, where he built a new city called akhetaten “‘ horizon of the disk.” thither he retired with his court and gave himself up to the worship of the aten or disk of the sun. this deity had already attained to the dignity of a temple in thebes under amenophis iii., but akhen- aten raised him to still greater prominence by suppressing the worship of the old state god amenre‘-horus-of-the-horizon and probably, though less vigorously that of the other egyptian deities. the result was a monotheism, though probably not a strict one, showing an undoubted tendency to compromise with the old sun-cult of heliopolis. i'ragments of hymns to the disk, perhaps composed by the king himself, have been found; these do not differ in any essential respect from hymns to other egyp- tian gods, more particularly amenre‘, though as literary produc- tions they stand possibly a little higher. the religion of the disk as we see it was a contemplative worship with little or no trace of ethical content, and hardly justifies the encomiums passed upon it by some modern historians. akhenaten reigned at least 17 years. his wife was a woman called nefertete, of whose origin nothing is known, but who apparently fell into disgrace toward the end of the reign. the 83 couple had at least seven daughters, of whom the eldest died young, while two others married respectively sakere‘ and tut- ankhaten (later tutankhamun), who in turn succeeded their father-in-law on the throne. akhenaten’s new religion barely survived his death, but his neglect of home and foreign affairs had cost egypt her empire in syria-palestine and reduced her internally to a state bordering on chaos. bibliography.—n. de g. davies, the rock tombs of teil el amarna, archaeological survey, egy pt exploration society, 6 vol. (london, 1903, ctc.); t. m. davis, the tonb of queen tiyi (1910); the tombs of tlarmhabi and tonatankhamanon (1612). 1... :e. peet and c. l. woolley, the city of akhenaten, vol. 1 (london, 1923); howard carter and a. c. mace, the tomb of tutankhamen (london, 1923). see also mittheilungen der deutschen orient-gesellschaft, nos. 34, 46, 50, 52, 55 and 57. cle da) akron, ohio, u.s.a. (see 1.458), had a phenomenal growth in the decade beginning 1910, due chiefly to the demand for tires and other rubber products incidental to the expansion of the automobile industry. its area was doubled, and the popula- tion tripled, reaching 208,435 in 1920, of whom 5,580 were negroes and 38,021 foreign born. the aggregate value of manu- factured products rose from $73,158,000 in 1909 to $558,962,000 in 1919; the average number of wage-earners in the factories, from 15,831 to 65,054. this development was arrested by the general depression of 1920-1, but by 1925 it was estimated that the population had again reached the figures of 1920. the output of the factories in 1923 was valued at $406,836,922; their employees numbered 41,903. expenditures for health and sanitation increased from $53,231 in 1910 to $402,459 in 1923; for education, from $277,454 to $2,640,833. a new water system, begun in 19015, represented by 1924 an investment of $11,000,000. elimination of gracle cross- ings was begun in 1924. a new charter, which came into opera- tion jan. 1 1920, set up the office of city manager, but four years later his duties were transferred to a mayor elected at large. the city planning commission, created by the charter of 1920, secured the adoption of a zoning ordinance in 1922. the municipal university of akron was created in 1913 by the action of the city council in accepting the plant and endowment of buchtel college as a nucleus, the original institution retaining its identity as buchtel college of liberal arts in the university. in 1924~5 the total net enrolment reached 2,151. alabama (see 1. 459) in 1920 the population was 2,348,174, as against 2,138,093 in 1910, an increase of 210,081, or 9°8%. although the proportion of urban population was greater than in igo, yet, in spite of the marked development of mining and manufacturing interests, more than three-fourths of the in- habitants were still rural and chiefly agricultural. the urban population unhabitants of cities of 2,300 or more) was 500,317, the rural 1,838,857. the distribution of population by race was as follows: whites, 1,447,032; negroes, 900,652. during the decade 1910-20 the white population increased 17:8 %, while the negro population decreased 0-8°% due to male negro migration to northern industrial centres. the u.s. census bureau estimated the population of birmingham, the leading city of the state on july 1 1925, at 205,670—an in- crease for the five-year period of 27,400. other bureau estimates of the same date are: mobile 65,955, montgomery 46,481, besse- mer 21,975, anniston 20,531, gadsden 17,104 and selma 16,987. there were 256,099 farms in 1920, against 262,901 in igio0, a decrease due to the negro migration noted above; but there was a marked increase in total production. industries and transport.—three new lines of material prog- ress are notable: (1) the use of hydroelectric power; (2) the utilisation of the canalised rivers warrior and tombigby from the heart of the inland mineral district to the important port of mobile; and (3) the building of docks, owned and controlled by the state, at mobile. a private corporation completed two great dams across the coosa river, and in 1925 a third was in progress. the company supplies electricity for lighting and power to the chief centres of population and industry through- out the state; and in 1925 it had undertaken the construction of a system of dams on the tallapoosa river at cherokee bluffs. 84 the u.s. govt. has completed the wilson dam on the tennessee river at mussel shoals. | during the closing months of 1920 the first vessel of a fleet of government-owned and operated, self-propelling barges made its way down the mississippi river to new orleans and into the gulf, then to mobile and up the rivers to birmingham and cordova in the heart of the warrior coal-fields. a balanced tonnage, up and down stream, is steadily being developed by the transhipment at mobile of manganese ore from brazil, for use in making high-grade stcel in the birmingham district, and by the establishment of an all-water freight rate from new york and other eastern points, via mobile, to the various river ports. an amendment to the state constitution having authorised the use of the credit of the state for the construction of a great system of docks at mobile, an act of the legislature at its session of 1923-4 authorised the issue of $10,000,c00 of bonds for that purpose and a commission was put in charge of the work. the commission thereupon acquired for the state ap- proximately 4oo ac. of land, with a water frontage of two miles on the northern outskirts of the city. the greater part of the pig-iron produced in alabama and not used in the manufacture of steel is made into cast-iron pipe, mostly in the birmingham district. since 1910 there has been a remarkable development of the cement industry, due to the presence of practically inexhaustible deposits of limestone in the heart of rich coal-fields, side by side with extensive areas of shale and clay, in a territory served by adequate hydroelectric power. alabama furnished 60% of the domestic graphite used in the world war. education—the legislature passed an act, approved feb. 6 igiq, creating a commission of five members, appointed by the governor, to make a study of the educational system of the state with the object of determining its efficiency. the commis- sion in turn invited the u.s. bureau of education to accept the task. the result was a series of acts passed by the legislature in 1919, constituting the school code of alabama. among the most important of these acts was one providing for astate coun- cil of education to co-ordinate the efforts of the university of alabama at tuscaloosa, the alabama polytechnic institute at auburn and the alabama technical institute and college for women at montevallo, by assigning to each special fields for higher education. taxation and finance.—alabama has neither state income nor state inheritance taxes, while its constitution of rgo01 limits the state property tax to 0o-65% upon assessed values... under the revenue laws in force at the end of 1925 both real and personal oroperty valuation for taxing purposes was placed at 60% of a reasonable cash value. under an amendment to the constitution, the legislature provided for a $25,000,000 bond issue, to be matched by a like amount from the federal govt. to be used in constructing highways connecting the several county seats. histery—during the period 1916-25 the government of alabama remained in the control of the democratic party, with only nominal opposition by the republican party, the educa- tional, property and other qualifications for voters under the state constitution of r90rt having eliminated the bulk of the negro republican voters. only in the presidential election of t920 were there indications of the development of a white republican party in the state. in that election that party polled 31:9 % of the vote cast, thus securing the privilege of a primary for the nomination of candidates in the next election at the expense of the state government. before this time factional differences in the democratic party were fought out in the primary elections under state supervision and the general elections were merely formal ratifica- tions of the choices made in the primaries. it was not easy to distinguish clearly between the two leading factions that devel- oped in the dominant party, but perhaps the terms conservative and progressive sufficiently indicate the line of cleavage. the former insisted on the fullest protection to vested financial interests, and before the adoption of the eighteenth (prohibi- tion) amendment to the constitution of the united states, ona aland islands—-alaska liberal policy of local option in the manufacture and sale of alcoholic beverages. the latter stood generally for strict con- trol, by the state, of corporate capital, especially in the matter of railway rate regulation and for prohibition of the liquor traffic. several amendments to the state constitution of rgor were adopted during this period, most of them dealing with matters of local interest to counties and cities. two, however, were gen- eral in their scope: one providing for local option by counties and school districts as to increased taxation in the interest of public schools; the other authorising the issue of state bonds to the amount of $25,000,000 for the construction of a complete system of highways, thus enabling the state to secure the na- tional appropriations in aid of that policy. at its regular session in 1919 the state legislature refused to ratify the nineteenth amendment to the constitution of the united states providing for woman suffrage; but as soon as the requisite number of states had made it a part of the constitution, a special session of the legislature was called (1920) which promptly passed an act providing for the registration of women voters and for otherwise carrying into effect the provisions of the amendment. governors after 1910 were braxton b. comer (dem.), 1907-11; emmet o’neal (dem.), 1911-5; charles henderson (dem.), 1915-9; thomas e. kilby (dem.), 1919-22; and william w. brandon (dem.), 1922- (t; cy dhe) aland islands: see aaland islands.",
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