RFA'TRW'S. 



mun-MIC. RATION. 



Tin- M Ignition of liirils. — Hy T. A. Cowarp. 137 paKcs. 



4 illustrations. ()|-iii. x 4l-in. (The Cambridge Manuals of 



Science and Literature.) 



(Cambridge University Press. Price 1 - net.) 



To write on the subject of bird-migration within the limits 

 of a small manual is an act of some courage, but Mr. Coward 

 may be congratulated on the success with which he has 

 accomplished his work. It is however significant of the state 

 of mind which the subject seems to induce to find the penulti- 

 mate chapter headed " Suggestions and Guesses " ; reliable 

 .md definite conclusions seem still far to seek. In the earlier 

 chapters a good and clear account is given of theories which 

 have been promulgated, old and new. and many of the facts 

 and incidents ascertained by observers in different countries — 

 the British Isles, liurope and North America — are stated and 

 drawn upon in illustration. These are full of interest, even 

 although sometimes more like curiosities of natural history 

 than anything else. Ornitbophaenology, " the accumulation 

 of substantiated observations and facts." Mr. Coward remarks, 

 ■■ will not prove everything" (page 6). but it might be added 

 that without these, properly co-ordinated and classified, 

 nothing can be proved. Such systematic work would prove, 

 in the end, more useful and satisfactory than theories and 

 speculations. 



A good bibliography is given, and although it is stated that 

 a full one has not been attempted, yet it is curious to find 

 mention of only two of the long and still continued series of 

 " Reports on the Movements of lairds in Scotland," and none 

 at all of the British .Association " Reports on the Migration of 

 Birds" (1880-1887), or of the current series of reports published 



by the British Ornithologists' Club. 



H. B. W. 



CHF.MISTKV. 



The Clicinistry of the Radio-Elements. — By F. Soudv, 



F.R.S. Monographs on Inorganic and Physical Chemistry.] 



92 pages. 8j-in. X 6-in. 



(Longmans. Green & Co. Price 2/6 net.) 



The process of specialisation in different branches of 

 Chemistry has reached such a stage that no one can hope to 

 keep in touch with the whole of the science. Moreover, even 

 in the special branches, the literature is so widely scattered 

 throughout scientific journals all over the world, that import- 

 ant contributions may readily escape notice. These drawbacks 

 have already been met in the case of biological chemistry by 

 the publication of a valuable series of monographs, the object 

 of which has been to summarise the present state of our 

 knowledge of the particular subject, and to serve as a sign- 

 post to those who are travelling in the same direction. 



This idea has now been e.\tended, and in the present 

 monograph we have the first of a series intended to deal in a 

 similar manner with different branches of inorganic and 

 physical chemistry, each to be written by an acknowledged 

 authority. 



In the book under consideration we have an excellent 

 outline of the new subject of radio-chemistry, and a summary 

 of the results of the most recent investigations. .After a 

 general description of the nature and phenomena of radio- 

 activity, sections are devoted to each of the ladio-active 

 elements, including the interesting cases of potassium and 

 rubidium, and the book concludes with a table of references, 

 an index, and a chart illustrating the genetic formation of the 

 elements successively produced in the disintegration of 

 uranium, actinium, and thorium. 



In .1 future edition it would be an improvement if the 

 references were classified under their respective headings. 

 With this exception we have nothing but praise for the book, 

 which m.iy be heartily reconuuended both to the research 

 student and to the general re.ider who has some slight know- 

 ledge of chemistry and is interested in its latest developments 



in this direction. /-ah 



C. A. M. 



.-l Text-Book of Iiiorfiaiiic Chemistry. — G. Sknter, 

 D.Sc, Ph.D. 583 pages. 90 illustrations. 7l-in. X5-in. 



(Methucn & Co. Price 6/6.) 



The appearance of new text books on inorganic chemistry 

 has now become so perennial, that on meeting with a fresh 

 addition to the list one's first thought is to discover why it was 

 written. In the present instance, the answer and the justifica- 

 tion are not far to seek, for the increasing application of 

 physical methods to chemistry, which has led to such striking 

 developments of the latter science, has rendered both desirable 

 and necessary the writing of an elementary text-book dealing 

 with the subject from modern points of view. In this aim the 

 author has been completely successful, and his book should 

 meet with a warm welcome in many quarters. It covers 

 more than the ground usually included in the examinations for 

 the London B.Sc. but at the same time cannot be described 

 as a " cram-book " ; for practical work and the application of 

 general theory to particular instances are skilfully interspersed 

 throughout its whole course. For instance, the physical 

 methods of determining the molecular weights of substances 

 in solution are described early in the book, and their use is 

 continually illustrated in the succeeding pages. 



As those who are acquainted with Dr. Senter's book on 

 physical chemistry would anticipate, an immense amount of 

 information is conveyed in the clear yet concise words of the 

 born teacher, while diagrams are introduced wherever 

 necessary to the text. In short, the book marks a great 

 advance upon the text-books of only a few years ago. which 

 described masses of more or less isolated facts in the arbitrary 

 manner that was inevitable, since important links which bound 

 them together had not yet been discovered. r A \f 



gf:ology. 



Geological and Topographical Maps; Their Interpreta- 

 tion and Use. — By A. R. Dwerryhouse, D.Sc, F.G.S. 

 133 pages. 90 figures. 9-in. X6-in. 

 (Edward Arnold. Price 4/6 net.) 



This book fills a gap in the technical literature at the 

 disposal of the teacher of geology, and is therefore assured a 

 wide welcome. It opens with a good general account of 

 topographical maps and their interpretation, in which one is 

 pleased to note an insistence on the importance of the true 

 scale in drawing both topographical and geological sections. 

 In teaching, however, it is often very difficult to present 

 geological structure to students without some exaggeration of 

 the vertical scale. True scale drawing should only be 

 introduced after the elementary principles have been mastered. 

 A useful summary of the characters of the various maps 

 issued by the Ordnance Survey of this country is given with 

 explanation of the system of numbering and method of order- 

 ing. The brief and necessarily sketchy chapter on some 

 structural features of the earth's crust might have been 

 expanded to some purpose. 



The problem of the relation of geological outcrops to 

 contour lines is treated as following from th'e general problem 

 of the mode of intersection of two contoured surfaces, one of 

 these being the surface of the ground, the other the geological 

 stratum considered. The directions of \'-shaped outcrops in 

 valleys is deduced easily and naturally on this method. In 

 succeeding chapters the complications due to inclined and 

 folded strata, unconformities, overlaps, and faults, are dealt 

 with ; together with the methods of representing igneous and 

 metamorphic rocks in plan and section. The principles thus 

 brought out are then applied to the elucidation of geological 

 history from maps, and some very instructive examples are 

 given. 



The concluding chapter gi\es some practical adxice to 

 geologists on the methods of conducting a geological 

 reconnaissance. This should prove most useful, as many 

 geologists have but slight ac<iuaiutance with topographical 

 surveying, without which geological work in a little-known and 

 umnapped country is not only more difficult but loses much of 



