November 4, 1909] 



NA TURE 



material collected and presented in the two volumes 

 and the atlas of this book, give us, first of all, a most 

 important apcrfu geologique of the DanaUil country, 

 French Somaliland, and southern Abyssinia as far as 

 Addis-Abeba, and a petrographical study of the same 

 regions, with analyses of the rocks and minerals 

 collected, and many photographs to show the types 

 of landscape. These photographs arc most con- 

 scientious, but the country presented to our eyes 

 between Addis-Abeba and the Gulf of Aden is cer- 

 tainly one of the least alluring of all Africa. The 

 Sahara Desert is much more attractive from the 

 painter's point of view. 



Some fjeetles were collected and are described. 

 There is a most important article (taking up a con- 

 siderable proportion of the second volume) on the 

 anthropology and ethnography of southern .'Vbyssinia, 

 by Dr. R. Verneau, of the Paris Museum of Ethno- 

 graphy. This is accompanied by admirable photo- 

 graphs of skulls, of clothing and adornments, of 

 musical instruments, pottery, jewellery, and horse 

 harness ; but the photographs taken by the expedition 

 of living human types are, with one or two exceptions, 

 not good or trustworthy, since they have been too 

 much touched up in order to make them presentable 

 pictures, or else they are very minute. The author of 

 this section (\'erneau) would seem to have arrived 

 at the following general conclusions : — That in the 

 portions of Abyssinia and northern Ethiopia in which 

 the Duchesne-Fournet expedition collected skulls and 

 took careful measurements of the living body, there 

 were, besides the pure-blooded Negro, three distinct 

 human types: — (i) The Amhara or Abyssinian (with 

 which might also be grouped the Gala ; (2) the nigri- 

 tised Abyssinian (simply the result of ancient and 

 modern intermixture between the Hamite — Abyssinian, 

 Gala — and the Negro) ; and (3) a most interesting 

 form, the Berber (this is a short title for the descrip- 

 tive term given by Dr. Verneau, who calls it, "Type 

 Abyssin clair, h cheveux lisses ou ondul^s," and else- 

 where, " Berbere "). This "third ethnic element" he 

 describes as "very different from those which I have 

 already set apart." It is one which has made its 

 influence felt in Abyssinia, but, like the Negro 

 element, it has crossed with the Hamite o'r Ethiopian 

 (type No. i), and as the result of this mixture its 

 characters have become sensibly attenuated. " Never- 

 theless, one may affirm that this type No. 3 is of a 

 fair complexion, slightly cuivre, and is further notable 

 because it has evidently lightened the complexion of 

 the skin in I3'5 per cent, (approximately) of the actual 

 population." "Type No. 3," he goes on to say, "has 

 blue eyes, or must have had blue eyes originally ; for 

 one could scarcely derive the blue, grey, or green iris 

 (which is that we have noted in the proportion of 

 ii'7 per hundred amongst modern .\bvssinians) from 

 the Ethiopian or the Negro. It is also type No. 3 

 w-hich has certainly introduced the smooth or very 

 slightly undulating hair, which has been found in 

 13'2 per cent, of the individuals under examination. 

 On the other hand, this light-skinned race has not 

 introduced tall stature amongst the people, but rather 

 lessened the stature of the Abyssinians as compared 

 with that of the Hamite and negroid races farther 

 south." 



In this race, Dr. Verneau apparently sees a 

 marked resemblance to the Kabail of Abyssinia. One 

 of the skulls depicted seems to display affmities with 

 the Cro-magnon race of Western Europe. 



There is a most comprehensive bibliography of 

 Ethiopia in this work under review, a work which 

 whets one's appetite for a complete examination of 

 Abyssinia. H. H. Johnston. 



NO. 2088, VOL. 82] 



THE SYSTEMATIC MOTIO\S OF THE 

 STARS.' 



A SYSTEMATIC character in the proper motions 

 ■^*- of stars was discovered by Herschel, and 

 accounted for by the motion of the solar system in 

 space. Herschei's conclusions were for a lime dis- 

 puted by Bessel, but were confirmed by .Argelander, 

 and have since been generally accepted. In the last 

 quarter of a century many determinations of the direc- 

 tion of the solar motion have been made, but the 

 results have not shown that accordance which might 

 have been anticipated. Particularly noticeable are the 

 different results obtained from the proper motions de- 

 termined by .\uwers of the stars observed bv Bradley 

 in 1750, and re-observed about iSbo, according to the 

 method employed. Applied to these stars, the mathe- 

 matical methods of attacking the problem developed 

 by .Airy and .Argelander place the solar apex, or point 

 to which the sun is moving, in declination -1-35° or 

 thereabouts, while Bessel's method places it at —5°. 

 In 1S95, Dr. Kobold directed attention to these dis- 

 crepancies, which seem to point to an error in the 

 fundamental hypothesis underlying these methods of 

 determining the direction of the solar motion. These 

 methods are based on the assumption that the 

 "peculiar" motions of the stars are haphazard, and 

 have no preference for any particular direction or 

 directions in space. 



As an outcome of prolonged study of the subject. 

 Prof. Kapteyn announced, in 1905, at the meeting of 

 the British Association in South Africa, that this 

 hypothesis was untenable. He used the well-deter- 

 mined proper motions of 2400 stars extending from 

 the pole to 30° south of the equator given in Auwers- 

 Bradley. Dividing this area of the sky into twenty- 

 eight regions, he determined the directions of the 

 apparent proper motions of the stars in each 

 region, and found that they showed a preference 

 for tiuo special directions and not for one onlv. 

 When these favoured directions for the twentv- 

 eight areas were plotted on a sphere, they were seen 

 to converge to two points. Convergence to a point 

 on the sphere indicates that the apparent linear 

 motions of the stars are parallel, just as the radiant 

 point of a meteor stream indicates the direction in 

 which the m.eteors are all apparently travelling. 

 Relatively to the sun, therefore, the stars are moving 

 in two streams, inclined at a considerable angle to 

 one another; these motions are apparent onlv, and, 

 when the solar motion is subtracted, are resolvable 

 into two streams moving in diametrically opposite 

 directions, relatively to the centre of gravity of the 

 stars. Kapteyn showed that the stars were equally 

 distributed among the two streams, ;ind that their 

 relative motion was in a line in the plane of the 

 Milky Way, directed towards the star $ Orionis 

 (R-.-A. 91°, decl. + 13°) and the opposite direction. 

 The apparent motions of the stars are thus resolvable 

 into a combination of (i) a haphazard motion, (2) the 

 reversed solar motion relative to the centre of gravity 

 of the stars, and (3) the stream movement in the 

 direction of ^ Orionis and the opposite direction. It 

 was pointed out by Kapteyn that the determinations 

 of the solar motion made by Airy's method, the one 

 most generally adopted by astronomers on account of 



1 (i) J. C. Kapteyn, Reports of the British Association for the Advance- 

 ment of Science, 1905, p. 257. 



(2) A. S. Eddington, Monthly Notices of the Royal Astronomical Society, 

 1906, vol. Ixvii., p. 54, and vol. Ixviii., pp. 104 and 588. 



(3) K. Schwarzschild, Nachrichten von der Koniglichen Gesellschaft der 

 Wissenschaften zu Gottingen, 1907, p. 6r4, and February, 1908. 



(4) S. Beljawsky, Aitronomische Nachrichten, Band clxxix, p. 293. 



'5) F .>y- Dyson, Proceedings of the Royal Society of Edinburgh, :9o8, 

 vol, xxviii., part i., p. 23r ; 1909, vol. xxix., part iv., p. 376. 



