628 



NA TURE 



[October 26, 1905 



but perfectly regular differences. The position of the 

 absorption bands varies with the mass of the colour- 

 less ion, and certain other facts have been observed 

 of the same character. Prof. Kayser reviews most 

 carefull}' the whole of the evidence of absorption 

 spectra that has been brought forward both for and 

 against the ionic hypothesis; he finally concludes that 

 Ostwald's theory, namely, that the behaviour of dilute 

 aqueous solutions of coloured metallic salts is due to 

 the colour of the ions, is untenable. Such an authori- 

 tative statement, based on experimental evidence, is 

 very striking and worthy of careful consideration by 

 physical chemists. 



The third chapter has been written by Prof. Hartley, 

 and deals with the relation between absorption and 

 chemical constitution. It contains an excellent 

 resume of all the work which has been carried out, 

 chiefly by Prof. Hartley himself, on the bearing of 

 ultra-violet absorption to molecular structure. The 

 value of this work is too well known to need 

 emphasising here, and it is not too much to say that 

 this is one of the most important branches of spectro- 

 scopy, and one that is certain to lead to results of far- 

 reaching importance in organic chemistry. 



The two last chapters deal in detail with absorption 

 spectra ; in the fourth chapter are described the spectra 

 of many substances, selected either because they are 

 of some practical use, or because they possess some 

 special point of interest, while the fifth and last 

 chapter contains an alphabetical list of all substances 

 the absorption of which has been measured. 



Of the great value of this book it is impossible to 

 speak too highly ; it is sufficient to say that it will 

 rank as the standard work upon absorption. All who 

 read it will appreciate to the full the great care Prof. 

 Kayser has bestowed upon it and the immense labour 

 involved in dealing with the mass of literature upon 

 the subject. E. C. C. B. 



OUR BOOK SHELF. 



Identification por las Impresiones digito-palmarex 

 (La Dactiloscopia). By Dr. Alberto Yvert. 

 Pp. III. (La Plata: A. Gasperini, 1905.) 

 This work is the thesis presented by the author to 

 the University of Lyons in order to obtain a doctor's 

 degree in medicine. It deals, firstly, with the uses to 

 which identification by means of finger-prints can be 

 put by the detective, and shows how the fingers of 

 the murderer leave their impression printed in the 

 blood of his victim ; while those of the burglar may 

 be brought to light on the window through which 

 he has passed, by the simple expedient of breathing 

 on it, and may be indelibly recorded by means of 

 hydrofluoric acid; and, lastly, the finger-marks of the 

 forger may be revealed on the cheque which he has 

 forged, by means of Mr. Forgeot's method. This last 

 record is produced, first, by the sweat of the fingers 

 that rest on the paper, which, when it evaporates, 

 leaves an invisible print behind it in the salts which 

 were contained in it. This may be made to appear 

 by the application of an 8 per cent, solution of nitrate 

 of platinum, which is affected by these salts in such 

 a way that it blackens when exposed to light. 



The author proceeds subsequently to the most 

 important part of his work— a summary of the 

 NO. 1878, VOL. 72] 



principal methods of classification of finger-prints. 

 He commences with a somewhat inadequate descrip- 

 tion of the original system, which, as is well known, 

 is that of Francis Galton ; he then goes on to treat 

 with much fuller detail some of the various systems 

 which are based on it. Among these are included 

 that of M. E. K. Henry, which has been adopted by 

 M. Windt, chief of the Identification Service of the 

 Police in Vienna; that of M. Pottecher, chief of the 

 Immigration and Identification Service in Saigon; 

 and of Senor Vucetich, director of the Identification 

 Service in La Plata. It is the last system which is 

 preferred by the author. It consists in dividing all 

 finger-prints into four types, which he names as 

 follows: — (i) Arco = arch; (2) PresiUa interna = 

 internal loop; (3) PresiUa e.vfcrKa = external loop; 

 (4) Verticilo or Torbf/i/no = spiral. These terms are 

 descriptive of the figures formed by the lines situated 

 near the centre of the palmar surface of the distal 

 phalan.x of each digit. As all ten fingers are taken 

 into account in the classification, and as each may 

 be of any of the above four types, there are 4'" 

 ( = 1,048,576) classes defined in this way. The minute 

 details of the arrangement enable one to distinguish 

 between different members of the same class. 



The pamphlet concludes with a useful bibliographv. 



E. H. J. S.' 



Science in South Africa: a Handbook and Review. 



Prepared under the auspices of the South African 



Governments and the South .African Association for 



the Advancement of Science. Edited bv the Rev. 



W. Flint and J. D. F. Gilchrist. Pp. x-l-489. 



(Cape Town, Pretoria, and Bulawayo : T. Maskew 



Miller. 1905.) 

 Those members of the British Association who 

 were fortunate enough to visit South Africa this 

 year cannot fail to have benefited by this useful and 

 handsome volume. To those who were unable to 

 accompany the association, but who take an interest 

 in scientific work in South Africa, this " index book " 

 will be a great boon. Of late years. South African 

 scientific literature has increased at a great rate, but 

 the material frequently lies scattered in numerous 

 publications often difficult of access, while so many 

 divergent opinions on the same subject have been 

 expressed that the student is apt to be bewildered. 

 From the present volume the status quo of scientific 

 research in South Africa can be ascertained. A long- 

 felt want is thus supplied, and if the scientific litera- 

 ture is to increase at the same rate in the future as 

 it has in the immediate past, a year-book on similar 

 lines would be of inestimable value. 



The cost of publication of the present volume has 

 been defrayed by the various South African Govern- 

 ments. In doing this they betray an enlightened 

 policy, for there can be no question that it will direct 

 attention to the vital importance of scientific know- 

 ledge in a country so vicariously treated by nature 

 as South Africa, where the natural products are dis- 

 tributed in such a way that they can only be utilised 

 by the application of the discoveries of modern science. 

 To those so trained. South Africa becomes a land of 

 fertile promise. 



The present volume is arranged in eight sections, 

 dealing with physical, anthropological, zoological, 

 botanical, geological, mineralogical, economic, educa- 

 tional, and historical problems. The sections and 

 subsections are the voluntary contributions of actual 

 workers, to whom the editors have allowed con- 

 siderable latitude as to the method of treatment. 

 In some cases the subjects are dealt with historically, 

 in others from the practical point of view. The 

 volume contains numerous illustrations, among which 



