COLOUR

the sensation of white light is caused by electromagnetic waves of a certain wave length impinging on the retina of the eve. the sensation of colour is produced by the ab- sorption of one or other of the coloured components of white light when the light strikes some suitable surface or passes through a suitable medium—the light reflected from the surface or trans- mitted through the medium consequently conveying to the retina a sensation of colour complementary to that absorbed. general and sclective absorptton—many substances do not absorb any definite portion of the visible spectrum—the name applied to the range of colours into which white light can be resolyed—but give geicral absorption throughout the range. such substances appear, therefore, colourless both by trans- mitted and reflected light and it is only those materials which cause selective absorption, that is which absorb some definite portion of the visible spectrum, that appear coloured. it follows, therefore, that there must be some special property possessed by substances which produce the sensation of colour which distin- guishes them from other substances that appear colourless. physical and chemical colour —aas a matter of fact it is quite easy to detect the causes leading to the main underlying differ- ence between the two types, for they may be divided int: two classes which, for the sake of convenience, may be named the physical cause and the chemical cause; and, in the first instance at any rate, the reason for production of colour is quite clear and it is a comparatively simple matter to reproduce the effect mechanically. for example, white light is resolved into its com- ponent colours when it is allowed to impinge on a glass surface which has been ruled with a number of fine lines, and there are a number of other ways by which the sensation of colour can be imparted by purely mechanical means. subjective colour.—as a matter of fact many natural objects, especially in the animal kingdom, owe their colour to the physical cause. the vivid green of certain beetles, the colours of the pea- cock’s feathers, the colours of butterflies’ wings and the colour of blue eyes are all produced in this way, the colour effect being caused by the interference of white light through the agency of minute excrescences or fine filaments on the surface of the objects that appear coloured. the colour effects in such cases are, there- fore, subjective and it would be just as reasonable to attempt to extract a coloured substance from the peacock’s feather as it would be to do so from the rainbow. chemical colour—on the other hand there are a great num- ber of substances the colours of which must be ascribed to the second or chemical cause. these occur both naturally and arti- ficially and are distinguished from those of the first or physical section by reason of the fact that the coloured substances in them can be extracted from the coloured materials and, when extracted, are found to be definite chemical compounds which owe their colour to their chemical constitution. colour the colours of flowers——in nature such coloured substances are to be found mainly in the vegetable kingdom, in the colour- ing matters, for example, of the flowers and of green grass or leaves. moreover, it is easy to distinguish by a practical test between the two types because if a peacock’s feather is viewed by transmitted light the brilliant colours will disappear, whereas, if a red rose leaf is treated in the same manner no change in colour will be noticed. intermolecular and intramolecular interference-—nevertheless, it is only reasonable to suppose that the two types of phenomena are of the same order and that whilst the physical or subjective colour is due to the iiermolecudar interference of white light, the chemical colour is due to intramolecular interference, or, in other words, white light is “‘ filtered ’ through the molecular structure of the chemical substance, leaving a ‘‘ portion ”’ behind in its passage. the colour is therefore depenc2nt on the chemical composition of the particular compound. it remains then to compare those chemical compounds which produce colour with those that are colourless so as to reach some conclusion as to the influence of molecular structure on colour production. in the first place, however, it is necessary to attempt to arrive at some definition of what is meant by colour in a strictly scientific sense. the visible spectrum in the range of electromagnetic vibra- tion.—the range of the visible spectrum which is produced, for example, when a beam of white light passes through a quartz prism, represents a range of electromagnetic vibrations of wave lengths between ,000 and 8,000 angstrem units. this is, how- ever, only one octave in the range of 62 octaves of wave lengths from o-or to 3-510! angstrem units which has been investi- gated. it is clearly, therefore, scientifically mlogical to restrict the term “‘ coloured ” to those substances which cause absorption only in the short region capable of detection by the eye, because a substance which produces selective absorption in anv other region of the electromagnetic range 1s also “ coloured ” although such colour requires the aid of some external influence in order that it may be detected. visible and invisible colour.—it 1s necessary, therefore, to dis- tinguish between visible colour and invisible colour and to de- scribe those substances which give selective absorption in the visible region as visibly coloured and those which give selective absorption in other regions as invisibly coloured. infra-red and ulira-violet regions.—it is fortunate that the photographic plate is more sensitive to waves immediately out- side the visible region of the spectrum than is the eye, for by its aid it is possible to detect selective absorption in those regions immediately outside the visible spectrum, which are known as the infra-red and the ultra-violet, and thus to show that many substances which appear colourless to the eye possess neverthe- less intense invisible colour. moreover, it is possible by simple chemical reactions to transform compounds having this invisible colour into those having visible colour or, in other words, by a change of structure, to throw the absorption from the invisible region into the visible region. in this way it is possible to corre- jate structure with visible colour. invisible colour of benscne.—for example, the hydrocarbon benzene (csh.s) appears colourless to the eye both by reitlected and transmitted light, nevertheless when its spectrum is photo- graphed marked selective absorption in the ultra-violet region cie c=o ~ os cil cit ci ch | | \ { ch ch ci cr s ee ch | — i. il. benzene (invisibly coloured) quinone (yellow) is manifested. benzene is, therefore, a substance having a strong invisible colour. by a simple series of reactions it is possible to transform benzene (i.) into quinone (ii.) and by so doing 681 to shift the absorption from the invisible to the visible region of the spectrum, thus obtaining visible colour (yellow). the shift of absorption —this change, in the case of many de- rivatives of benzene, takes place with remarkable ease and with astonishing rapidity, thus the change from phenol-phthalein (iii.), the benzenoid or invisibly coloured form, tu the sodium salt (iv.) the quinonoid or visibly coloured form, by the action of alkali, and the reverse change which is effected by the action of acid, is so rapid and sensitive that the substance is used as an effective indicator in alkalimetry. we ss ; , an pa g se (/ 0h alkali c eo = 7 ——74 an aie oc as ee ee): ere a <a co—o coona 108 e iv. benzenoid form quinonoid form (invisibly coloured) (red) the hydrocarbons naphthalene (ciohs) and anthracene (cul) provide further examples of the same kind and, in fact, the occurrence of colour among organic compounds which has led to the foundation of the coal-tar colour industry is based mainly on this change. it is also possible to start with a benzenoid derivative which by reason of its structure is visibly coloured and by a simple chemical change, such as that illustrated above, to throw ab- sorplion from one end of the visible spectrum to the other and thus to transform a red substance into a blue one. red and blue flowers.—as a matter of fact nature has utilised this method to produce her red and blue flowers :— cl , bs on re ol hoy s/sc—z sow _alkali_ 110 c= = 0 | a / acid | we “ey — a ss a oh ch oll ch red blue (rose) (cornflower) the red flowers are those in which the cell sap is acid, the blue those in which it js alkaline. if the cell sap 1s neutral the flowers are purple. it would appear, therefore, that the occurrence of visible colour is mainly adventitious and depends on molecular conditions which are subject to control. it happens to be a property of the quinone ring because the parent substance benzene possesses the power of causing absorption just outside the visible region. even so, the formation of the quinone ring may not shift the absorption of benzene far enough to bring it within the visible region, and there are thus derivatives of quinone which have no visible colour. on the other hand the shift of the bands may be caused by other structures and there are, in consequence, deriva- tives of benzene such as azobenzene, cyl];~n—=n-—cehs, to which no quinone structure can be assigned, yet which possess strong visible colour. | infra-red absorption—if the wider definition of colour be accepted it is probable that there is no such thing as a colourless material, because it is likely that every substance gives selective absorption somewhere within the range of electromagnetic vi- brations. it appears to be in the power of many substances be- longing to the aliphatic series of organic chemistry to give selec- tive absorption in the infra-red region of the spectrum. visibly coloured substances in this portion of organic chemistry are not of frequent occurrence, but when such colour occurs it js always associated with the presence of what is known as the conju- gted system of double linkages; thus glyoxal (v.) and diacetyl (vi) are yellow:— ik aes a ie cho—c=0 | h---c=0 clis—-c=0 ch,o—c=0 (v.) eae (vil) 682 methyl oxylate (vii.) is, however, visibly colourless and it must be assumed that in this case the infra-red absorption has not been thrown into the visible region. it is of interest to note that the same system of conjugated linkages is present in the con- ventional formula for benzene (1.), the definition of “colour.”’—it is also significant that visible colour is shown only by unsaturated carbon compounds and that in no case has a visibly coloured saturated compound been pre- pared. it follows therefore:— 1. that both visible and invisible colour are associated with un- saturation. 2. that they are associated with the occurrence of selective ab- sorption either outside or within the visible region of the spectrum, the former causing invisible, and the latter visible colour. 3. that occurrence of this absorption is bound up with the pres- ence of a system of conjugated double linkages within the molecule. colour in inorganic chemistry—the causes leading to the production of visible colour in inorganic compounds will not be clearly understood until more is known about the molecular structures of such substances. it 1s obviously due, initially, to the presence of a colour-producing element such as copper, chromium, cobalt, etc. the cause of colour in these elements is probably molecular, as instance the change im colour iodine undergoes when heated. nevertheless the structure of the salt must also play a part as is shown, for example, in the disap- pearance of the blue colour of hydrated copper sulphate when it loses part of its water of hydration. in any case the causes of visible colour in this section of chemistry are not so clearly defined as they are in the organic section, and no useful purpose would be served by dealing with them in the present state of our knowledge. bibliography.—c. graebe and c, liebermann, berichte der deuischen chemtschen gesellschaft, vol. 1, p. 104 (1868); sir w. n. hartley, phil. trans. roy. soc., vol. 170 (1899); w. ostwald, ‘* ab- sorption spectra of solutions,” zeits. f. physikalische chemie, vol, g (1892); dr. h. kauffmann, ' farbe und konstitution,” ahren’s vortrdge, vol. 9 (1904); sir w. w. ilartley in h. kayser's handbuch der spektroscopte, vol. 3 (1905); r. willstatter, ber. d. deutschen chemischen gesellschaft, vol. 41 (1908); h. ley, die beziehungen zwischen farbe und konstitution bet organischen verbindungen (1911); r. willstatter, ber. d. deutschen chemischen gesellschaft, vol. 47 (1914); m. wheldale, the anthocyanin pigments of plants (1916); e. r. watson, colours in relation to chemical constitution (1918); a. g, perkin and a. e. everest, the natural organic colour- ing matters (1918); g. c. t. von georgtevics, die beziehungen zwischen farbe und konstitution bet farbstoffe (ztirich, 1921); hon. v. a. h. onslow, phil. trans, roy. soe. 3., vol. 211 (1923). (jj..th. colour and race, problems of.—the narrowing of the world by improved transport, the levelling of mankind by the spread of education, and the increase of wealth and rise in social position of coloured peoples are bringing the races into relation- ships which may provide the most difficult problems of this century. the progress of civilisation is threatened by the serious danger of racial conflict and the still more serious evil, the demoralisation caused by inter-ractal and colour prejudice. i. primary races mankind, according to most authorities, includes three primary divisions or races which are as difficult to delimit as the breeds of dogs. according to some authorities the three races are so different that they should be regarded as distinct species; but the fact that all their members can interbreed and produce - fertile offspring is weighty evidence of their specific unity. in opposition to the view that the human races are specifically dis- tinct is the claim that there is no real difference between them, and that the apparent distinctions are no more significant than those variations in complexion, head form and size, that occur between members of the same family. that claim is based on the differences between the extremes of any one race being greater than the difference between the races. this overlap, how- ever, no more proves the invalidity of racial distinction than the fact that a bee has more points in common with mankind than it has with a barnacle is evidence that man is an insect. colour and rach, problems of the characteristic which seems to be most constant and use- ful in the classification of man is the hair, which marks off three primary races: in cymotrichi (wavy-haired), leiotrichi (smooth-haired), ulotrichi (woolly-haired). the division into these three races is now generally accepted. apart from the hair the physical characters of each of the races vary so greatly that their definition is difficult. the main distinctions are remarkably stable, for the negro and the caucasian are clearly represented in early egyptian pictures, and the three races were probably distinct 1n the stone age. as haddon points out, ‘‘ the ancient egyptian artists who decorated the royal tombs at thebes in the xviii. dynasty distinguished between four races: (1) the egyptians, whom they painted red; (z) the asiatics or semites, who were coloured yellow; (3) the southerners or negroes, who naturally were painted black; and (4) the westerners or northerners, white. we ourselves speak loosely of white men, yellow men, black men, red men and brown men.”’ the correspondence between colour and races founded on hair form is not complete. the negro has woolly hair, the straight hair belongs to the mongolians, while the caucasian peoples have wavy hair. the negroes vary in colour from chocolate hue to a brown which is so dark that it is often called black; the hue of the american section of the mon- golian race differs so much from the typical yellow that the american aborigines were called the red indians. the cauca- sians include the whites of europe, the brown races of asia, north africa and australia, and some of the blackest of the african tribes. characteristics —the social and intellectual differences are well marked, though in these respects the races overlap. as re- gards courage, endurance and self-sacrifice the three races are not unequal. the brown people have contributed to prog- ress most of the chief handicrafts and the founders of all the chief religions—buddhism, confucianism, hinduism, islam and christianity. the mongolian is characterised by steady industry, high skill in craftsmanship and habitual self-surrender to his community. the negro, on the other hand, has a strong individu- ality which is less adapted to political stability and social coherence; he generally lives in village communities, which, except where ruled and organised by non-negroes, have never united into a powerful or wide-ruling nation. the caucasian race is not a political unity; for it is divided into the white section or european, including therein the white settlers in the other continents and the brown caucasians, who are grouped with the mongolian and the negro as the coloured section of mankind. the european people have shown the greatest capacity for initiative, combination and subdivision of work, and have thereby subdued the forces of nature, achieved the infinite complexity of organisation required for success in industry on a great scale and yoked the powers of steam and electricity. the european in administration has by his success rendered inevitable a readjustment between the white and coloured sections of man- kind. the white nations during the past four centuries, owing to the mental alertness due to their superior education, have gained world-wide supremacy—commercial, political, military and intellectual. they have established their dominion and direct rule over cight-ninths of the habitable land of the earth. yet they number only one-third of its inhabitants. the recognition of european superiority in some respects and the benefits received from the european’s skill in administration have made many eastern and african people accept his help and even his rule. the ballads of bengal, recently collected and published by dines chandra sen, show that in the 16th century northern india under its mogul rulers was in appalling disorder. british rule has contributed to the country’s prosperity and peace, and european influence has frequently had that effect elsewhere. the european commercial pioneers were either preceded or followed by missionaries who often gave important secular help and faithfully upheld the interests of the native population when they tended to clash with those of the trader. hence the growth of european influence was often welcomed. the chinese, for example, appreciated not only the work of the early jesuit mis- colour and race, problems of sionaries, but the help of the european staff in its imperial customs service. the eastern people also prized the benefits of european trade; but they could not have had much share in it without giving european capital and traders the security of extraterritorial privileges, which lapse as the necessity for them disappears. in time, however, the material disadvantages of foreign control, the galling symbols of inferiority, religious fanati- cism and the mistakes of government have led to reaction. reaction.—the control of the world by the european peoples is a comparatively recent development and may be onlv tem- porary. the uprising of national sentiment since 1goo has already lessened the european domination. the most important single factor in this change was the russo-japanese war of 1904. japan, alarmed at the attempts to exclude her or her influence from the adjacent parts of the mainland of asia, attacked russia, and by brilliant victories secured control of manchuria and struck a resounding blow at european prestige. in india the rise of the professional class with the spread of western education, the irri- tation of some genuine grievances and the stimulus to indian nationalism by the japanese success led to the establishment of partial indian self-government by a measure which contains the machinery for its further extension. the establishment of a republic in china with its remarkable development of scientific and educational activity among the intellectual classes of that country, the recovery by afghanistan of the management of her foreign affairs, the wresting by arabia of its independence from turkey and the establishment of egypt as an independent sultanate are some results of the growth of asiatic nationalism. european problems.—europe is a mass of racial problems. the surge from the east which brought the magyars into the heart of europe, the pressure of the turk, the thrust of the alpine race to the plains and peninsulas, the clash of slav and tartar and mongol in russia, have played, and still play, a decisive part in shaping the political conditions of europe. differences of culture, religion, language and institutions go with differences of race, and, in southeastern europe, the tangled mountains enhance the separatist tendencies of the folk that dwell there. contact with northern africa and the mediterranean littoral is of great antiquity. the population of portugal has a strong african element. the moorish occupation of spain has left its mark on the characteristics, physical and political, of the spanish people. the population of southern italy and sicily contains ele- ments of african origin. the population of the south of france is very mixed. the extension of the french and italian colonial empires to africa has enlarged the area of contact, and with it, the range of problems. the mediterranean peoples historically dis- play a comparative readiness to absorb coloured groups, while the nordic stock holds aloof from such intermarriages. asia is firmly held by the mongolians and dark caucasians. africa is the home of the negro and of a negro-dark caucasian intermixture in the north, and taking the continent as a whole, the pure whites are in a small minority. native influence tends to increase. the three other continents are the possible heritage of the european, though north america may have to absorb a considerable proportion of negro, and australia will have to ac- cept inevitable delays in the cultivation of its tropical lands by white labour. from tropical and sub-tropical countries come the raw materials which europe needs for her factories. these areas are valuable markets for european products. the problems vary with the historical circumstances in which european control was established in each area, and with the local political and economic conditions... ii. the british commonwealth thus race problems in the british commonwealth are of ex- treme complexity, for its autonomous dominions, with their dif- ferent circumstances and traditions, necessarily adopt different labour and immigration policies. this differentiation is possible so long as each dominion shows reasonable consideration for the responsibilities of the empire as a whole, and is prepared to tolerate the limitations involved in partnership. canada.—the racial problems in canada are comparatively simple, in spite of the complications due to the french-speaking 683 population, which is increasing in numbers and spreading west- ward both in quebec and ontario. the indians of canada are few and of no political importance. the colour line is an issue only in british columbia, where there has been a considerable immi- gration from india, china and japan in the past, though it is now insignificant. the main racial problem in canada concerns the mixture of the present population, which is derived from north- western europe, with immigrants from eastern and southern europe. a vast immigration of italians and slavs has been flow- ing into the united states; and canada, like that country, may restrict her slav and italian immigrants. south africa—in south africa the position of ‘‘ the poor white ”’ forms a serious problem. south africa has an extremely mixed population, for both the white and coloured sections are composite. the white settlers include dutch, british and some french huguenots. the coloured population consists of negroes from many different south african tribes, the descendants of west african negroes introduced in the 18th century, and asi- atics. the west african negroes and asiatics have given rise to the class known as the cape boy. the european position in south africa has been weakened by the feud between british and boer due to difference of ideas on native policy. it early led to the quarrel over the abolition of slavery, and is still shown by cape colony having granted the negro the franchise, which is refused him in the other south african states. the racial problem in south africa illustrates the difficulty of maintaining a fair standard of life for the less efficient members of a dominant minority. in the effort to save the position of the white artisan the south african govt. proposes the policy of segregation. no white man can settle in some parts of south africa without the sanction of the governor-general; and it is proposed that in some areas certain occupations should be reserved to the white artisan. the principle of segregation was adopted by the natives’ land act of 1913, and its extension was proposed in measures under con- sideration in 1925. it is opposed by many capitalists on the ground that it will raise the cost of labour; but the elections in south africa in 1924 show that a large section of the white popu- lation regards some plan of segregation as indispensable for the maintenance of the european position. tropical africa——in tropical africa the race policies are based upon two different principles. in west africa the govt. acts as the trustee of the native, and protects him against the sale of his ground or produce on unfavourable terms. the native is encouraged to become a small holder and cultivate his own land. the resultant increase in numbers and wealth of the population has given the europeans probably greater prosperity as mer- chants than they would have achieved as planters using native labour. in kenya (east africa) european settlers were invited to develop the fertile lands beside the railway, large land grants were given and the natives were expected to enter the service of the europeans. the indians, including many who had been employed in the construction of the railway, spread through the country and were especially useful in retail trade with the negroes. the extension of european plantations has now created a greater demand for labour than the population can supply. more labour is required to reap a harvest than to sow the crop. hence efforts have been made to discourage the natives from working in their reserves and to force them by taxation and other means into the european service. the problem in kenya colony is how to work both the native reserves and the european estates without forced labour, which has been rejected by the responsible leaders of each of the three british political parties as approx- imating to slavery. the opposition of europeans in kenya to the further immigration of asiatics has been strongly criticised by indian public opinion. australia.—australia is the one continent which is blest with the absence of any inter-racial problem. when european coloni- | sation began it was inhabited only by a few nomads. after the federation of australia in rgor, the white australia policy was adopted, and the coolies who had been imported to work the sugar plantations were sent back, excepting those who had made homes 684 in the country. the queensland sugar industry was thus left dependent on white labour. despite emphatic predictions to the contrary it has continued to develop. its success, the health of the people of tropical queensland and the general trend of medi- cal opinion (sec, for example, gregory, menace ef colour, chapters 8 and 9) show that tropical australia can be developed by white labour provided the standard of life be maintained by the absence of coloured labour. india.—india presents inter-racial problems of peculiar dif- ficulty due to the great diversity of race, language and religion. the population is mainly dark caucasian, with some mongolian elements and in the south possibly a negro strain. racial differ- ences are vital in india. much evidence has been collected by indian scholars in support of the view that the caste system is in origin a colour reaction of a dominant light-skinned group which, by its superiority, imposed hegemony and its institutions upon the indigenous, darker-skinned stocks. caste is varma and varna is colour. in the south where the dark-skinned proto-indics (sce races of mankind) are most numerous, the segregation of the lower groups is still a feature of the social polity. the languages are a babel, and the two chief creeds, hinduism and islam, repre- sent the very antithesis of religious thought. the problem for the govt. of india is how a small oligarchy can harmonise the conflicting interests of 320 millions of such diverse people. the growth of indian nationalism has led to an extensive measure of self-government, which has so far proved only a partial success. the establishment of elective councils is a mark of the faith of the british govt. in the depth of british influence in india. the spread of western education has rendered many indians capable of taking a responsible part in the administration of the country. iii. the united states in the united states, after the civil war of 1861-5, the negro was given his freedom and endowed with full political rights. then followed a period after 1867, which was known as the “ re- construction,” when the southern states suffered from deplorably incompetent and corrupt government. in 1876 the northern states, distressed by the failure of the system which they had forced upon the south, withdrew support from the “carpetbaggers” and allowed the whites in the southern states to resume control. by trickery, fraud and legislative measures, some of which, such as some clauses in the oklahoma constitution, in recent years have been declared unconstitutional by the supreme court, the negro was practically disfranchised. negroes were excluded from many universities, schools and theatres used by the whites, especially in the south; they were debarred even from the churches and from such organisations as the young men’s christian association, unless they founded separate centres of their own. they complain and, according to many independent investi- gators, with justice, of unfair treatment in the law courts, which is not surprising as the judges and officials are appointed by public election in which the negro has no vote. moreover, in 29 of the states intermarriage between whites and negroes is illegal, and according to the virginia ‘‘ act to preserve racial integrity : of 1924, no marriage in that state is legal between a white person and any person who has a trace of non-caucasian blood other than one-sixteenth or less of american indian. the policy of racial repression seems now impracticable. it has led to increasing bitterness which has been remarked by many observers during the past 20 years. it is held responsible for the fierce race riots in 1919 at houston, texas, at washington, d.c., chicago, elaine (ark.), east st. louis, knoxville (tenn.), omaha (neb.) and bogalusa, louisiana. ‘the traditional south- ern policy toward the negro may become impossible owing to his migration to the northern states. ‘there the negro has long enjoyed, theoretically, all the rights of a full citizen. in the words of lincoln he is ‘‘ in his right to eat the bread he earns equal to any other man ”’; but the northern system prevented him from earning his bread except in small numbers in menial employments. the conditions are now changing in consequence of the immigration restriction act of 1917 and the still more rigorous act of r924. labour scarcity compels the northern colour and race, problems of manufacturers to turn to the south for negro labour. southern agriculture, and especially the cotton crop, is dependent on the negro. yet the movement of negroes to the northern towns, if continued, may embarass the southern states industrially. the u.s. dept. of labor (bulletin 1924, p. 35) enumcrated as the causes of the migration ‘‘ poor wages, poor housing, abuses due to the overseer system of farming, inadequate educational facilities, the ‘ jim crow’ law, inequality in law enforcement, the labor contract law which renders possible the peonage sys- tem, mob violence and disfranchisement.” the negroes them- selves at a representative conference in atlanta, ga., declared that the migration was due to their complete loss of faith in the willingness of the white people ever to treat the coloured people justly. this migration actually brings southern colour problems to northern thresholds. iv. the policies contrasted as the permanent subjection of one race by another appears under modern conditions impracticable, as well as unjust and undesirable in the interests of both peoples, the available policies are reduced to assimilation or independent evolution. the policy of assimilation means that the race question might solve itself by the fusion of the races by intermarriage, since the absorption or extinction of the weaker race appears to be the inevitable result of co-residence. fusion.—according to some authorities race prejudice is so mischievous that the world would be much happier if the races were completely fused. many observers in the united states consider that racial feeling there is becoming less acute, and that the repression is being reduced as numerous half-castes form a complete transition between white and negro. the policy of fusion is supported on the ground that intermarriage produces superior offspring. ‘the success of some european nations has been attributed to the varied qualities which they have inherited from their mixed ancestry. the crossbreeding of races which are nearly akin is often bene- ficial. ‘‘ heterosis,” or hybrid vigour, has been proved experi- mentally by the crossbreeding of plants and domestic animals. the evidence is weighty, however, that the intermarriage of races that are very different produces offspring inferior to either parent. herbert spencer recommended japan to avoid the inter- marriage of japanese and europeans. national character is a hereditary complex, which has been developed by gencrations of natural selection. the interbreeding of two stocks of which the hereditary complex is slightly different may be expected to lead to improvement, but if they are very dissimilar the progeny will probably be inferior. herbert spencer’s view has been reaffirmed by many modern eugenists as the result of careful investigation of such cases as the intermarriage of the scandinavians, who are teutonic, with lapps, who are mongolians. segregation.—the third policy is the independent evolution of the different races when geographically separated in mass, under conditions which allow of such individual intercourse through missionaries, teachers, men of commerce, scientific experts, administrators, etc., as will enable the races best to co- operate in the development of the world. the conditions in most of south and central america illustrate the results of racial fusion. independent evolution is possible in the other continents. conclusion inter-racial hatred is one of the serious menaces to human progress. men of different races engaged in a joint enterprise olten work together harmoniously and with true affection; but race hatred easily develops where men of different civilisations compete side by side for the necessaries of existence. the repulse of the negro capacity for affection is the bitterest element in his lot, as expressed by the negro poet, paul lawrence dunbar:— because i had loved so deeply, lsecause t had loved so long, go. in his great compassion, gave me the gift of song. colour photography—colours of animals because i had loved so vainly, and sung with such faltering breath, the master in infinite mercy, offers the boon of death. to avoid such poignant disagreement the most hopeful policy available seems to be segregation in mass, combined with such individual intercourse as will enable the different races to help each other, without arousing the violent repulsion generated when people of dissimilar cultures and colours meet with grating fric- tion in competition for their daily bread. bin_iography.—general: t. lothrop stoddard, the rising tide of colour against white world-supremacy (1920); j. 1. oldham, christianity and the race problem (1924); j. w. gregory, afenace of colour (1925). united states: mary roberts coolidge, chinese immigration (1909); h. p. fairchild, immigration. a world move- ment and its american significance (1913); bulletin of u.s. census bureau, no. 129 (1915); w. e. b. dubois, darkwater (1920); stephen graham, children of the slaves (1920); ii. j. seligmann, the negro faces america (1920); the negro yearbook (tuskegee, 1922 and 1925). south america: sir h. h. johnston, the negro in the new world (1910); f. garcia calderon, latin america, its rise and progress (1913); helmer key, european bankruptcy and emtgra- tion (1924). asia: m. w. townsend, asta and europe (1913). africa: the vearbook of the union of south africa; m.s. evans, black and white in the southern states (1915) and black and whate in south east africa (1916); sir f. j d. lugard, the dual afan- date in british tropical africa (1922); w.c. willoughby, race prob- lems in the new africa (1923); norman leys, kenya (1924). austra- lia: statistics in the yearbeok of the commonwealth of australia; sir j. w. barrett, the twin ideals (1918). racial interbreeding: fast and jones, inbreeding and ontbreeding (1919); j. w. gregory, menace of colour, ch. 8 (1925). chee oe colour photography: sce photography.