HWANG-HO

a reconnaissance of the flood- stricken delta of the hwang-ho was undertaken by the ameri- can red cross in 1911 and 1914; a promising series of observations by the kiang-hwai engineers under h. e. chang chien was begun in 1011, and a critical review of these previous findings was made in the field in rg19g—20 by john r. freeman, partly in connection with his work for the grand canal improvement board. through the province of shantung the hwang-ho’s fall to the sea has been found to be about 1 in 5,000, a steep gradient for so large a river. the current is therefore very swift, and the river not only carries along great quantities of sediment, but the muddy bottom itself steadily works forward and the bed of the channel is raised. measurements by freeman’s staff show that the river carries over 4°% by weight of silt, and may even carry 13% in greatest flood. naturally the stream drops a part 399 of its heavy burden whenever its velocity decreases. three types of deposit are to be considered: outside the outer dikes; between the dikes; and along the river bed within the main channel. deposits outside the outer dikes.—when the river overflows or breaches the outer dikes, it deposits over the land a sloping ridge of sediment which varies greatly in size, but probably during the past 1,000 years has not exceeded the equivalent of ro ft. close to the main dike, tapering off to almost nothing at 5 or 10 m. away. deposits between the inner and the outer dikes.—whenever the river lloods the space between the outer and inner dikes, the waters as they subside deposit their silt and a flood plain is formed. these flood plain deposits between the dikes, while varying from 12 to 20 ft., average 15 ft. above the low-water level. probably they accumulate somewhat rapidly. it ts this very action which can be utilised to form a permanent barrier of surpassing strength if the river be trained as freeman suggests (proc. amer. soc. civil engt- neers, may 1922, pp. 1113-67). _ deposits within the main channel.—when the summer floods sub- side, the river, in narrowing to its winter channel, slows up and de- posits sediment on its own bed. although much has been written about the yellow river continually raising its bed, compelling the inhabitants constantly to build the dikes higher, there were no facts upon which to base such statements until the red cross in i914, and the grand canal improvement board in 1919, gave cross sec- tions, extending far beyond the dikes, showing broadly the relation of the elevation of the river bed to that of the adjacent country. these show that the river has done remarkably well in conveying nearly all of its silt to the sea, ancl that the rise of its bed has been extremely slow, in general not more than 15 ft. during the past 1,000 years, or perhaps 2,000 years—say a foot a century. great as the river’s land deposits have been, they are small in comparison with the total volume of sediment transported in 1,000 years, if the river during that time carried anything like the percentage of sedi- ment recently observed. it appears that the ycllow river during all the historic period has carried to the sea 99°, of the burden of silt gathered in the loess country. the flow of the yellow river varies much with the season, being ordinarily three times as great in flood as at low water. in the summer of 1919 a flood flow of 265,000 cu. ft. per sec. was measured (the highest for 10 years) with a minimum of 10,600 cu. ft. per second. this is remarkably small, considering the great extent of the drainage area; much of it, however, is a land of little rain, and the losses on the way are very large. moreover, this river has no tributaries for some 300 m. from its mouth. its only connections are with irrigation and navigation canals which serve during high- level periods to draw off water. though practically uscless for navi- gation, the yellow river may, in spite of its relatively small discharge and variable flow, be a blessing in the way of drainage and irrigation if it is properly dealt with. (c.k es) hyatt, anna vaughn (1876- }, american sculptor, was born at cambridge, mass., march ro 1876. educated at a private school at cambridge, she commenced the study of art in boston, proceeding later to new york city. there she studied a short while with h. a. macneil and gutzon borglum, under whose influence she acquired that knowledge of horses which is so signally exemplified in some of her works. she devoted her- self chiefly to small bronzes. her equestrian statue, “ jeanne d’arc,” was selected for riverside park, new york city, in 19gt3, and copies of it were erected at gloucester, mass., and blois, france. this work, a “ saint joan of arc ”’ in the cathe- dral of st. john the divine, new york city, and a “ diana” have been her chief figure compositions. notable among her other works is a colossal ‘* lion on a boulder ” executed for the dayton high school. in 1923 she married archer milton huntington. hyde, douglas (1860- ), irish scholar and writer, was born at frenchpark, co. roscommon, 1860, and was educated at trinity college, dublin. in 1891 he acted as interim professor of modern languages at the university of new brunswick, can- ada. he formed in 1893 the gaelic league, for the preservation and extension of the irish language, and was president of that body until rors. in 1899 his production, before a vice-regal committee on education, of letters from leading celtic scholars throughout europe saved the irish language on the interme- diate board which regulated the curricula for irish schools. during 1905 he toured america and raised £11,000 for the gaelic league. on his return he was appointed a member of a royal commission on irish university education. dr. hyde was made professor of modern irish at university college, dublin, in 400 1909. he was co-opted by the free state senate in 1922, but failed to secure re-election in 1925. in the latter year he became editor of lia feii. the movement created by him initiated an enthusiasm for the native language, which finally resulted in the teaching of the language being made compulsory in irish schools. among dr. hyde’s more important works are a literary history of ireland (1 50a): collections and translations of the love songs of connacht (1893); raftery’s irish songs (1904); the retigious songs of connacht (1906). he also wrote several short plays in irish. hyderabad, sir mir osman ali khan, nizam of (1886- }, was born april 6 1886 and succeeded his father, sir mir mahbub ali khan, on his death on aug. 29 rg11. his education had been under an english tutor, sir brian egerton, and a nobleman of the state, of scholarly attainments, imad ul mulk (saiyid husain bilgrami). soon after accession he aban- doned the traditional system of governing through a diwan, and for five years was his own prime minister. in 1919 he constituted an executive council with a president and eight other members, each in charge of one or more departments. during the world war he enjoined on his subjects the duty of firm and steadfast devotion to the british cause and prohibited anti-british propa- ganda in his dominions. the war expenses of the state amounted to over three-fifths of the annual income. his eighness, already a g.c.s.1., was awarded the g.b.e., was promoted to hon. lieutenant-general in the british army, and in tor8 king george v. conferred upon him the new and special title of exalted highness. hydroelectric engineering.—the extent to which hie water powers of the world have been investigated and de- veloped during the past decade forms one of the striking engi- neering features of the period. although falling or flowing water formed the earliest of the natural sources of energy to be utilised for providing power, some two-thirds of the water power at present in use has been developed since 1910. the reasons for this are partly technical and partly economic. the technical development of electric generation and trans- mission has made it economically possible to utilise powers remote from any industrial centre, while the great developments in electrochemical, electrophysical and metallurgical processes have provided an outlet for such energy as could be cheaply developed. most of these processes require relatively large amounts of energy, and all are economically dependent on the cheapness of this energy. they have created a demand for large blocks of cheap power which can, under favourable circum- stances, be satished more readily from a water-power installation than from any other source. developmenis—the urgent demand for energy to supply the abnormal requirements of the war period, combined with the increased cost of fuel, was responsible for an unprecedented rate of development in those countries having available water-powcr resources and normally dependent on imported fuel. ‘thus in france something like 2,500,000 of water-horsepower is now de- veloped as compared with 750,000 h.p. in 1914. in switzer- land, the present output is 1,500,000 ii.p. as compared with 880,000 h.p. in 1914. in italy it is estimated that the total output will shortly amount to 3,000,000 horsepower. japan, which only recently began to investigate her water- ewes: has, since 1916, developed over 1,200,c00 h.p., or about 20% of her available resources. step by step with developments on the electrical side, advances have been made in the design of hy- draulic turbines. these various developments have made it commercially possible to make use of large water-power at sites quite remote from any centre of industrial activity. in many cases industrial communities, attracted by the cheapness of the power, have grown up around such sites. in others the energy has been transmitted electrically for long distances, in some cases between 200 and 300 m., to some more convenient centre. available water power—an estimate, based on papers pre- sented to the world power conference at london in 1924, and on other sources, indicates that the amount of water-power, hy derabad—hydroelectric engineering respectively available and developed in some of the chief coun- tries of the world, is approximately as follows:— millions of horsepower devel- oped avail- able 09 23-0 great britain canada 0-25 : 3°28 australia africa (east) africa (south) africa (west) british guiana. india and ceylon new zealand papua british empire 5 including son =) he g) c= es w = yv ~ austria south america dutch east indices france (sermany italy japan . norway russia . spain sweden switzerland united states bey kwai ot! oo 30 from these figures it appears that some 200,000,000 h.p. is available, of which approximately 27,000,000 is at present developed or in course of development. uses or hydroelectric energy while a large proportion of the energy developed from water power is utilised for industrial purposes and for lighting and traction, an increasing proportion is being used for pulp and paper making and electrochemical and electrometallurgical proc- esses; indeed the chief outlet for hydroelectric power in the near future is likely to be in connection with such processes and, probably, railroad electrification. the amount of power already used in electrochemistry is large. thus the world’s production of calcium carbide alone requires some 500,000 h.p. and when it is remembered that such products as aluminium, carborun- dum, chromium, cyanamide, caustic soda, chlorates, magnesium, phosphorus and silicon are only rendered commercially possible by such processes, 1t will be realised that the future demand for energy for their manufacture is certain to be large. nitrogen fixation is also likely to make great demands. in norway alone some 400,000 h.p. is available for this purpose, and in view of the rapid depletion of the natural nitrate deposits, from which four-fifths of the world’s nitrogen consumption has hitherto been supplied, and of the diminution in fertility of many of the great wheat and cotton growing areas of the world, the production of artificial fertilisers by one or other system of nitrogen fixation must, in the near future, become a question of great importance. ruilroads.—the electrification of railroads has made rapid strides of recent years. in the united states some 3,300 m. of track have been electrified, while the chicago, milwaukee and st. paul railway has the longest electrified section in the world (8so m.}, the power for operation being obtained from hydro- electric stations. in france, much of the track of the compagnie du midi in the region of the pyrenees has been electrified with the aid of water power, and it is anticipated that the whole system of about 3,c00 km. will be electrified within 10 years. the hydroelectric stations supplying these lines havea capacity of close on 300,000 horsepower. the orleans co. has a scheme for electrifying 3,000 km. of its lines, part of which is to be supplied from hydroelectric stations having a capacity of about 210,000 horsepower. in austria some 1,800 km. of line is in process of electrification for which 120,000 h.p. is available from hydro- electric stations. in germany about 1,200 km. is now electni- fied, its electricity coming from hydroelectric schemes. much of the swiss railway system has been electrified, and the elec- trification of further trunk lines in these and other countries hydroelectric engineering is at present under consideration. such developments will open up a very large field for the utilisation of water-power where this is available. (see railways, electrification of.) agriculture —much energy is now being utilised in the united states of america for purely agricultural purposes. in california, for example, there is in effect one vast system of electrical supply extending over a distance of 800 m. with 7,200 m. of high-tension transmission lines. this is fed from 75 hydroelectricstations inter- connected with 47 steam plants, to give a total output of 785,000 horse-power. a further group of 13 hydroelectric schemes now under construction will add another 520,000 horse-power. a large proportion of this power is used in agriculture, and it is estimated that electric motors equivalent to over 500,c0o h.p. are now installed on californian farms. the californian rice industry is almost wholly dependent on irrigation made possible by electric pumping, whilst most of the mechanical processes involved in farming are being performed by electric power. the economic development of many of the tropical depend- encies of the british empire, whose latent wealth is practically untapped, is directly inter-connected with the development of their water-power resources. not only would an abundant sup- ply of such power enable railroads to be operated, irrigation schemes to be set on foot, and mineral deposits to be tapped and worked, but it would go far toward solving the labour problem which promises to be one of some difficulty in the future. while those outlets for electrical energy which are now in sight promise to absorb all the energy which can be cheaply developed for many years to come, there are many other prob- able directions in which such energy might find a new and prof- itable outlet. among these may be mentioned the purification of municipal water supplies; the dehydration of food products; and the preservation of timber. lay-out of hitydroelectric scitemes tigh head schemes.—the layout of a hydroelectric scheme depends on the physical characteristics of the catchment area and site. high head schemes are of necessity located in moun- tainous country and are usually fed from streams of relatively small volume. owing to this a comparatively small reservoir is often sufficient to provide suflicient storage of the head waters to give uniform output over a considerable portion of the year at a reasonable cost. the water may be brought directly from the reservoir to the power house through a pipe line or pressure tunnel if the gradient is suitable. often, however, it is possible to bring it through an open canal at a very flat gradient, to a forebay on the hill-side above the power-house, whence a short pipe-line conveys it to the turbines. low head schemes.—low head schemes are usually located on rivers where the gradient 1s small, the head being provided by a dam, or naturally by means of rapids or a waterfall. a river dam, by raising the natural level of the water, provides a cer- tain amount of storage, but seldom more than is sufficient to store the night flow for use during the day. such a scheme can therefore only give a continuous output equal to the dry weather capacity of the river, unless operated in conjunction with some steam station capable of equalising the output at such times. several types of low head layout are available. where a dam is built, the power house is often constructed on one flank of the dam with a short head race or tail race as is most convenient, and the dam itself is used as a spillway over which excess water is discharged in times of flood. where the river flows in a nar- row and steep gorge the power-house may sometimes with advantage be constructed in the dam itself, which now consists of a hollow reinforced concrete structure. where the river forms a long bend, it is often possible to cut across the neck of the bend and to utilise the head between the two points. afedium head schemes.—in medium head schemes—utilising between 40 and 200 ft. head—the layout is usually similar in broad outline to those involving either high or low heads. where such a scheme involves the use of a long closed supply pipe to the turbines, having only a small gradient, somewhat special treatment, however, becomes necessary. owing to the large 401 inertia of the column of water in the pipe line, any sudden demand for water caused by opening the turbine gates on an increasing load causes a relatively large drop of pressure at the turbines, which renders governing very difficult. to reduce this difficulty, a surge tank is fitted to the pipe-line at a point as near to the turbines as possible. this is a stand pipe surmounted by an open tank having a comparatively large surface area, whose upper level is slightly higher than that of the water in the reservoir. any sudden demand is then supplied in part by flow down the stand pipe and the drop of pressure is greatly reduced. at the same time any rise in pressure caused by suddenly closing the turbine gates is also reduced. in a low head station the available space is usually limited by the width of the dam on which it is built. in consequence, in such plants, there is a tendency to locate the switch gear and transformers either on floors above the machine-room, or, as is becoming more common, in an entirely separate building on the river bank. in some few cases all the transformers and high- hh! if hy io ‘sn n\ u hy," tore fddegy race mig. is js waz lss ja __——aa ss == power house —— in holiow ot fh ferro concrete oam ne fic. 1.—types of low-head development. tension switch gear are out of doors, and this will probably become standard practice in the future. it has even been pro- posed to place the whole generating plant outside, merely pro- viding a portable cover for use during repair work. the recently planned muscle shoals development in alabama was originally schemed along these lines. it has finally been decided to adopt the conventional type of station building, but the complete out- door generating station will doubtless arrive in the near future. turbines.—the inward flow pressure turbine and the pelton wheel are the only types of turbine used in modern hydroelectric schemes of any size. the type to be adopted depends largely on the available head. the pelton wheel is a slower running ma- chine than the pressure turbine and is therefore better fitted for very high heads. it has the further advantage for such heads, that since the water is discharged through one—or at the most two—nozzles, these may be of reasonable size when dealing with the small volumes of water normally available in high head schemes. the pressure turbine on the other hand with its full peripheral admission of water is well adapted to utilise the large volumes necessary in low head schemes, and its higher speed of rotation is also a great advantage in low and medium head plants, in enabling the cost of the electrical generators to be reduced broadly speaking the pelton wheel is more suitable for heads above about 700 ft.; the pressure turbine for heads below 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on 9 +69 ole 19°. ize ecs too fhe cela ase eos outer one 7 a ig a es bw oe a ol oe.” re he pa vb > j a ” : og co ee. ‘ oe oo: a =4 vi ¢ ° 2 ib - * fi . . pe pie en derg ire ce at en a. oo ec oes wre pttiye age ache earth ‘ er ent > mm tc mr aes ae oe ser ae tly er. ls ew 4 ants ce pah. ear tet er ae eae ar se hn site see 2 sr ar tee oe dre ik bee nee ry? seg so ae5 qe° *d05'. ete sac ove man ed : a as = = *, ae hg “ye ot pe 6 see ae it sop te af. os a i witte wee yee gn om. me ‘ el. t 0 tre ry ss rert ane br rs ps oe a . — < se usauee fray © 2:05.08 v = —— — — , see a schaal === eas og pe eae “ss e 6 ba" eo a & 7 a < ra) os = “eis > me ‘i ca ot y i i. * 7 4 2 6 3: +: . =o y _——— o* ee ae 2 sagim—mell kore ins ras sbgynsbn b34 s12 bees =< 2a ae cal os starr re fgrts eb: =y;, *y wees : vie od et daten hd arta 4 at ieee cy fic. 2.—hydroelectric station with outdoor transformers and high-tension switch gear. 14,000 k.v.a. under 80 ft. head. while over the intermediate range of heads much depends upon the size of the units and the special circumstances. all modern pressure turbines are of the mixed flow type, having inward radial flow through guide vanes surrounding the runner, and axial discharge. pivoted guide vanes are universally used, speed regulation being attained by simultaneous rotation of these about their axes. low head turbines—up to about 40 ft. head—-are usually set in an open forebay. either vertical or horizontal shaft machines may be used, but the former are becoming more common, especially for large units. for higher heads the water must be supplied through a pipe-line and the turbine is enclosed in a spiral casing so designed as to distribute the water evenly around the periphery of the guide vane ring. for heads up to about 120 ft. this casing may be moulded in concrete, but for higher heads and pressures a metal casing becomes necessary. this may be of cast iron, cast steel or of steel plate construction, and in order to give rigidity and in- creased safety in case of surges of pressure is sometimes em- bedded wholly or partially in the concrete of the substructure. modern development is tending in the direction of units having a single runner and a vertical shaft on the top of which the electrical generator is mounted. the weight of the shaft, runner and generator is then carried from a single thrust bearing of the michell or kingsbury type. this type lends itself to a simple and efficient form of setting, while the friction losses are ex- tremely low. one of the great drawbacks of the low head turbine in the past has been its relatively slow speed of rotation, which neces- sitated either a slow speed and costly generator or expensive gearing. asa result of experiment it has, however, been possible so to modify the form of the runner as greatly to increase the speed of rotation under a given head without seriously reducing the efficiency. such runners are characterised by their small number of vanes—often not more than four being used—and approximate in form to that of a marine propeller. in one of the latest types, hydroelectric engineering the kaplan, the vanes are capable of rotation about their own axes so as to enable the vane angles to be adjusted to suit the varying flow of water at part loads. further developments in the direction of increasing the speed are in active progress and promise to give important results. at the present time, how- ever, turbines are in existence which are capable of eflicient operation at spceds at least three times as great as would have been thought possible to years ago. the pressure turbine is now built in units capable of develop- ing upwards of 70,000 h.p. under a head of 300 ft., and this size could readily be increased if necessary. if well-designed and installed in a suitable setting the efficiencies are remarkably high. efficiencies of 93°% have been obtained on tests of vertical shaft turbines at niagara and values approximating 90°) are quite common. ina medium head plant the following are typical values :— fraction of full load percentage efficiency pelton wheels are usually built as horizontal-shaft units with one or two nozzles, and in sizes up to about 30,000 horse power. speed regulation is usually performed by a deilector which cuts off the jet from the wheel, acting in conjunction with a central needle or spear which slowly reduces the size of the jet while the deflector returns to its original position. the mechanism is operated by a relay cylinder supplied with pressure water or oil through a pilot valve actuated by the governor. in a well- designed plant the instantancous speed variation corresponding to a sudden application of full load should not exceed 12 to 15%. the difference between the initial and final steady speeds should not exceed 2°% between full load and no load, and should not exceed 5° with a load variation. at constant speed the efficiency of a pelton wheel falls off comparatively slowly as the load is diminished. a well-designed wheel should have approximately the following efficiencies: — fraction of full load percentage efficiency the lack of a suitable pipe-line has, until recent years, tended to retard the development of plants for very high heads. under such heads the necessary wall thickness, even with a moderate pipe diameter, becomes too great to permit of the use of riveted joints. recent developments in electric welding and oxyacety- lene welding have, however, rendered it possible to construct suitable welded pipes and by their aid, and by the use of solid drawn steel pipes in extreme cases, it has been found possible to harness some very high falls. the highest as yet utilised is at the fully installation in switzerland. here the working head is 5,412 ft., corresponding to a working pressure of 2,360 lb. per sq. inch. the pipe-line is 19.7 in. in diameter and 14 in. thick at its lower end, and each of the three pelton wheels in the power- house develops 3,000 horsepower. pipe-lines.—the pipe-line for a water-power plant may be constructed of steel, reinforced concrete or wood. stcel is the most usual, riveted pipes being suitable for all but the highest heads. for heads up to about 200 ft., reinforced concrete pipes are suitable and have the advantage of not deteriorating appreciably with age. as compared with steel pipes the materials are more easily transported and the friction losses are less. large pipes are moulded in site, and as the bulk of the materials is usually obtained locally, only the cement and reinforcement require to be transported for any distance. for small diameters, pre- moulded concrete pipes with loose-sleeve or spigot-and-faucet joints are often used. for moderate heads, wooden pipes are extensively used in countries where suitable timber is cheaply available, and under favourable conditions have a useful life of at least 25 to 30 years. they are built up of wooden staves about 6 in. wide, shaped to the correct radius and jointed end to end by thin metal plates driven into saw cuts on both the abutting ends, covering the joint. the staves are so arranged that the circumferential joints 403 are not continuous. they are held together by circumferential steel bands which resist the bursting pressure, and whose diam- eter and spacing depends upon the pressure to be anticipated in each section of the pipe. the matcrials are easily transported and neither erection nor repair require any great degree of skill. if suitable timber is available the mill can be set up on the site and only the bands and shoes require transporting. as heads and diameters increase the amount of steel necessary for the bands increases until it becomes comparable with that required for a steel pipe for the same duty. in general the range of useful heads is from 20 to 200 feet. these pipes have been constructed in sizes up to about 18 ft. in diameter. generation and transmission.—generators to be driven by hydraulic turbines range from the simple open-type machine which is often applicable to small units, to constructions ap- proaching those of steam-turbine driven alternators, which are necessary for the largest high-speed machines. at the present time the energy is almost universally gen- erated as alternating current, on account of the simplitity and reliability obtained with a moderate generating pressure which is readily transformed to the highest pressures which may be required for economical transmission. occasionally, however, the advantages of high-tension direct-current transmission may outweigh the essential difficulties of its generation, in which case the thury system is available. of the two types of alternating current generators, the synchronous and induction types, the latter has come largely into use in recent years, especially for automatic stations, on account of its robustness of construction and simplicity in operation. frequencics—the question of the most desirable frequency is simplified by the fact that in most countries two frequencies— a high and a low—have become recognised as standard. in the u.s.a. and canada, either 60 or 25 cycles per sec. is almost universally adopted; on the continent 50, 162 and 15; in great britain and south america 50 and 25 cycles. as regards the number of phases there is little freedom of choice, the question being largely determined by the nature of the load. single phase supply, though offering some advantage in simplicity of equip- ment, involves increased losses in the generators and gererally less reliable performance. this system is only used where abso- lutely necessary, as for direct supply to alternating current rail- ways using commutator motors. of the polyphase systems, three-phase is preferable to two-phase for general power pur- poses, since the plant is more fully standardised and therefore cheaper, while rotary converters are smaller, more effictent, and give better commutation on three-phase than on two-phase systems. distribution.—fyor distribution within a short radius of the power-house the voltage of generation and transmission will be the same as that required for the supply to consumers; but for transmission to greater distances, for which the voltage is stepped up, there is a wide choice of the voltage of generation. an unduly low voltage involves heavy and expensive bus-bars and switch-gear, and in large units presents difficulty in the construction of the stator windings of the generators. a very high voltage, on the other hand, requires a winding with many windings in series per slot, a greater thickness of insulation and involves a generally reduced reliability. i'rom the point of view of the construction of the generator it is desirable to have two conductors per slot, and the stator current should then vary from about 300 ampe€res in the smallest to 1,000 amperes in the largest machines. it may therefore be shown that the most suitable voltage of generation, when not otherwise restricted for a three-phase machine, should vary approximately as follows:— output ( kw.) pressure (volts) 200 | 500 1,000 }| 2,000 | 5,000 | i0,000 15,000 | 450 | goo | 1,500 | 2,500 | 5,000 9,000 11,000 the power factor is here assumed to be 0:8. for two-phase machines the phase pressure should be about o-9 times the above values. 404 one of the most important modern developments in trans- mission has been in the direction of reducing the losses by in- creasing the voltage of the transmission lines. (see electricity, transmission of.) automatic generating stations —the automatic generating station is especially suited to systems where numerous small- power falls are available. in such a case the expense of an operat- ing staff at each would be prohibitive, but if each station can be made automatic, and all are linked into a common distribution system, the labour cost is reduced to a minimum. the first of such stations was set in operation in 1917. this is on the system of the lowa railway and light co., where it operates in parallel with a steam plant situated about two miles away. the auto- matic station contains three soo-k. v. a. generators driven by francis turbines operating under a head of 1o feet. normally the starting and stopping of these sets is accomplished auto- matically through the medium of float switches actuated by the change in the jevel of water above the dam. provision is also made for controlling these operations as well as the gate open- ings of the individual turbines by push buttons in the central power-house. other plants of this type have since been in- stalled, and this method of development promises to do much to render it economically possible to utilise many low head river falls which have hitherto been neglected. combined operation of hydraulic and steam plants —owing to the variability of river flow, it is impossible to utilise more than a fraction of the total available cnergy unless machinery is installed which will have to be idle during the greater portion of the year. broadly speaking it is found that the most economi- cal results are obtained when the capacity of the turbines is such as will enable them to be run at full load for about six months in the year. by operating a steam plant in conjunction with the hydraulic installation, it becomes economically possible to increase the capacity of the hydraulic plant, the defect of its output at times of less than normal flow being made good by the steam installa- tion, the latter also serves as a stand-by in case of a breakdown of the hydraulic plant. (see supeer-poweer.) the best method of operation of such a combination depends upon the type of load, storage capacity, etc., and can only be determined by special reference to the special circumstances of each individual plant. very often, however, the steam station is entrusted with the special duty of carrying the peak load. (a. h. gt.) hygiene: see industrial welfare; public healtil. hymans, paul (1865- ), belgian politician, was born at ixelles, brussels, march 23 1865. he became a barrister in hygiene—hy the, conference of 1885, and from 1898 to 1914 was professor of comparative par- liamentary history at brussels university. from 1900 he was deputy for brussels and soon became the liberal leader. after a mission to president wilson in aug. 1914 he was plenipoten- tiary in london, 1915-7, when he became head of the ministry of economic affairs. from 1918-20 and 1924-5 he was minister for foreign affairs. in nov. 1918 he attended the inter-allied council at versailles; he also represented belgium at the peace conference in tgtg and on her behalf signed the peace treaty. in the same capacity he attended the conferences at san remo, boulogne, brussels and spa. he played a leading part in the settlement of the ruhr question, the dawes plan, the. se- curity pact and the economic union of luxembourg with bel- | gium. in jan. 1920 he was appointed belgian representative on the league of nations, and in the same year was made presi- dent of the first assembly at geneva. a member of the academie royale de belgique, m.hymans wrote l’histotre parlementaire de la belgique and frere orban. hyndman, henry mayers (1842-1921), british politician, was born march 7 1842 in london. his father was a barrister and founder of the ilyndman trust for building churches. after leaving trinity college, cambridge, he travelled extensively and became war correspondent for the pall afall gazette during the austro-prussian war of 1866. in 1881 he founded the social democratic federation and from this time on was the chief exponent of marxism in great britain. as such, he came into contlict with william morris and later with j. ramsay macdon- ald. hyndman opposed the south african war; took an active part in the second international; but, in spite of his sympathies with india’s demand for self-government he took a strongly imperialistic line at the outbreak of the world war in 1914. he died in london nov. 22 1921. qone of his latest books, the evolution of revolution (1920), clearly sets out his general views; in addition to numerous other propagandist works he also wrote records of an adventurous life (1911); further reminiscences (1912); and the future of democracy (1915). see rosalind t. hyndman, the last years of h. mf. hyndman (1923). hythe, conference of (may 15 to 17 1920), a meeting between the british and french prime ministers, together with the chancellor of the exchequer and the french minister of finance, in preparation for the conference of spa (see spa, conference of). <a french proposal that france should be granted priority in reparation payments seems to have been put forward but not pressed, and the linking up of the reparation problem with the question of inter-allied debts was proposed publicly for the first time in the official communique. ibanez—icelandic literature and politician, was born at valencia jan. 29 1867. he became an impassioned political agitator and suffered exile, hard labour and frequent imprisonment for his opinions, although he was returned to parliament on eight occasions by his native city. his carly novels, of which canas y barro is considered the best, deal with life in valencia and are in some respects superior to his later productions. although a republican, ibanez held strong anti-feminist opinions. he travelled extensively and achieved world-wide success as a writer for the cinematograph. among his best-known novels are la catedral (1903, english translation, the shadow of the cathedral, 1909); sangre y arena (1908, eng- lish translation, blood and sand, 1913); los cuatro jinetes del a pocalipsis (1916, english translation, the four horsemen of the apocalypse, 1918) and mare nosirum (1918, english transla- tion, our sea, 1920). he was unpopular in spain, where his writings were ignored by the majority, and he eventually settled in paris, becoming the centre of a group of politicians with anti-monarchical views. . iceland (see 14.227), an independent state in personal union with denmark. its area is 40,437 sq. m. and its population is about 100,000. in 1918 iceland was recognised as a separate kingdom, with unlimited sovereignty, in personal union with denmark. according to the act of union there are no real joint affairs; denmark, however, provisionally till 1940, takes charge of the foreign affairs of iceland as its mandatory. for the same period danish and icelandic citizens, residing in either state, enjoy in every respect equal rights. since 1915 iceland has had its own merchant flag; since 1918 its own national arms. abroad danish jegations act on behalf of both denmark and iceland. iceland has a legation in denmark, and denmark a legation in iceland; other states are represented in iceland by consulates. conslitution.—according to iceland’s new constitution (1920) the king shares the legislative power with the parliament, the althing, an assembly of 42 members, sitting in two divisions, the upper house (+4) and the lower house (28), but in cases of dissension it can assemble as a joint parliament. the cabinet consists of three ministers, but there is no governor-general, and every legislative act passed by the althing and many admin- istrative measures must be sent to the king in copenhagen for signature. since 1920 iceland has had its own supreme court, and (since rort) its own university. other improvements in education are the establishment of a teachers’ seminary and a system of public schools. in almost every other respect ice- land in this period has made constant and rapid progress. population—the total population in 1925 was 100,000 (1901, 78,000), about 50% living in towns and trading-stations. there are seven towns with chartered privileges, the greatest of which is the capital reykjavik, which has about 22,000 inhabi- tants (1901, 6,700). industry.—the fishing trade has been considerably improved by the introduction of new methods, especially steam trawlers and motor cutters, and the export of fish products, chiefly cured split cod, herring and fish oils increased from a value of 11,000,000 kr. in 1911 to 68,000,000 kr. in 1924. the cultivation of the soil is also constantly improving, though in a smaller degree, and dairy farming after the danish method has been introduced, by which the production of butter has been greatly improved. with the exception of several handicrafts in the towns there is almost no industry. some woollen factories have been established, and yield a good return, but capital is lacking to provide as many as are needed. water power.—in its innumerable waterfalls (the greatest and most accessible estimated to represent about 4,000,000 horse power). iceland is in possession of almost inexhaustible motive power, and it is very likely that considerable industries may grow up in iceland in the near future; both danish and nor- [== vicente blasco (1867— _—+), spanish novelist 405 wegian companies during the war petitioned the althing for concessions to utilise some of the greater falls. the realisation of this plan was, however, hindered partly by the icelanders’ reluctance owing to their fear of invasion of foreigners and partly by the common european economic crisis. thus far the water power has only been used to produce electric light in most of the towns and on some few farms. minerals.—the only mining industry is that of the precious cal- careous spar, only found in iccland, as the many rich sulphur mines and the lignite mines, worked during the war cannot pay on account of difficult transport to the coast. both iron and copper and even gold have been found, and english as well as german experts have declared that the working of the gold mines near reykjavik would be remunerative; here a german-dutch company was still engaged in preparatory investigations in 1925. | communications.—communications are constantly developing, and driving roads have been made in almost every district; bridges have also been constructed over most of the rivers, and a scheme for construction of a railway was in 1925 fully prepared by the government. a telegraph cable to shetland was opened in 1906, and telegraph and telephone lines inland have been extended prac- tically throughout the whole country. in 1917 a wireless telegraph station was erected in reykjavik and broadcasting (radio) intro- duced in 1925. the lighthouse system is yearly improving, and at reykjavik a modern harbour with quays and cranes has been built. in 1914 iccland acquired its own steamship company, which in 1925 controlled six mail steamers. public ifealth.—the birth-rate in 1923 was 26°5 per 1,000 and the death-rate 12:5 per 1,000, the latter showing a marked improve- ment on pre-war figures. a mental hospital and a sanatorium for tuberculosis, together with some other minor infirmaries, have been established and the building of a great state hospital in reykjavik was commenced in 1925. liquor control.—from 1912 onwards there came into force a system of complete prohibition of import and making of any liquor containing more than 2! °% of alcohol, with the exception of medical requirements and denaturalised spirits for industrial use. but in 1923 spain (the chicf market for iceland’s fish products) forced jecland to allow import and sale of spanish wines, while the prohibi- tion for the rest has been maintained. bruliograrny.—valtijr gudmundsson, sland am beginn des 20 jahrhunderts (1904); de danske atlanterhaver 7 island (1907); daniel bruun, routes over the highlands (1907); p. herrmann, island, das land und das volk (1914), starfskrd islands (1917) and dansk- islandsk forbundslov (1918); stjernarskred konungsrikisins island (1920); daniel bruun, hagsk¥rsluv islands (statistique de i’ islande), nos. i-44 (1914-25). (v. g.) icelandic literature (sce 14.240).—as in the previous period poetry takes the foremost place; although great progress was made in novel writing, and the drama also gained in signif- icance. among the many lyrical poets einar benediktsson and st. g. stephanson, resident in canada, were the most important, both rather heavy in style, but rich in ideas and weighty in thought. lighter and more elegant in style are david stefans- son, stefan fra hvitadal and hulda (pseudonym unnur bjark- lind), while the best novelists are einar h. kvaran and gunnar gunnarsson. gudmundur fridjensson, j6n trausti (pseudonym gudmundur magnifsson) and gudm. g. hagalinre portray folk life with considerable skill; so do j. m. bjarnason and laura salverson; both reside in canada and portray the life of the icelandic colonists there, the latter writing in english, e.g., the viking heart. the best dramatists are jehann sigurjensson and gudm. kamban, whose dramas achieved a great success at the royal theatre in copenhagen. the drama, the afother-in law, by an icelandic countrywoman, kristin sigftsdottir, was produced at reykjavik and winnipeg, and was much admired. among the more notable writers on other subjects were, t6n adlis, pall e. olason and jon helgason on history, j. th. thoroddsen on geography, and sigfus sigfisson on folklore. sigffis blendal published an icelandic-danish dictionary, the first complete dictionary of modein icelandic. brpliography.—hallder hermannsson, js/andica, vol. 6, 16 vol. (1908-24); icelandic authors of to-day (1913); sigurdur nordal, isienzk lestrarbok (1924); edmund gosse and w. a. craigie, the oxford book of scandinavian verse, p. 331-423 (1925). 406