6i8 



NATURE 



[July 14, 192 1 



putation " should be welcome to both students and 

 teachers in such places. 



The author has put into book form the course 

 of lectures he has been giving to engineering 

 classes in the mathematical laboratory at the 

 Massachusetts Institute of Technology. It is a 

 comprehensive course, including a discussion of 

 various kinds of scales and the slide rule, net- 

 works of scales for several variables, nomo- 

 graphic charts, empirical formulas (with the 

 method of least squares), periodic curves, inter- 

 polation, and approximate integration and differ- 

 entiation (with various kinds of planimeters, inte- 

 grators, integraphs, etc.). Each part of the 

 subject is dealt with in some detail, with the result 

 that the book is a mine of useful information on 

 practically all the processes that occur in com- 

 putative or graphical work. One may, per- 

 haps, think that the subject-matter is too 

 condensed both in treatment and in actual 

 print, but as a foundation for a course in a mathe- 

 matical laboratory the book can be recommended 

 without hesitation ; it should find a place in every 

 mathematical and engineering or technical library, 

 and serious students will find it a continual help 

 in their industrial or research work. 



A particularly exhaustive treatment from the 

 practical point of view is given of nomography. 

 Perhaps it would be better if the author had laid 

 more stress upon explaining exactly how nomo- 

 grams are to be constructed and used than upon 

 the reproduction of so many nomograms. This 

 is, however, a matter of taste, and what the 

 author has put into this section of the book is 

 on the same standard of excellence as the re- 

 mainder. There are numerous examples, many 

 of them worked out numerically in full. The book 

 also contains accurate charts of uniform and 

 logarithmic scales, as well as of square roots. 



S. Brodetsky. 



Our Bookshelf. 



Creative Chemistry: Descriptive of Recent 

 Achievements in the Chemical Industries. By 

 Dr. Edwin E. Slosson. (The Century Books of 

 Useful Science.) Pp. xvi -1-311. (London: 

 University of London Press, Ltd., 192 1.) 

 125. 6d. net. 

 This book is written by an American journalist 

 with some knowledge of chemistry. It is intended 

 for lay readers who wish to make themselves 

 acquainted with some of the recent developments 

 of applied chemistry, including nitrogen fixation, 

 fertilisers, dyes, sugar, rubber, poison gas, and 

 other subjects likely to be of interest to the aver- 

 age reader. The facts, which appear to be 

 accurate and selected with care and discretion, 

 are presented clearly and forcibly, with a certain 



NO. 2698, VOL. 107] 



native humour. Gerhardt should not (p, 6) be 

 described as a German chemist, while the account 

 of the origin of Kekul6's theory of the benzene 

 nucleus (p. 66) differs somewhat from that usually 

 accepted. It is also interesting to know (p. 33) 

 that "we might have expected that the fixa- 

 tion of nitrogen by passing an electrical spark 

 through hot* air would have been an American 

 invention [it was discovered by the English 

 chemist Cavendish], since it was Franklin who 

 snatched the lightning from the heavens as well 

 as our sceptre from the tyrant, and since our out- 

 put of hot air is unequalled by any other nation." 



A Little Book on Map Projection. By Mary 

 Adams (Dr. William Garnett). New and re- 

 vised edition. Pp. viii+112. (London: George 

 Philip and Son, Ltd. ; Liverpool : Philip, Son, 

 and Nephew, Ltd., n.d.) 5s. 6d. net. 



The second edition of this useful book differs little 

 from the first, which was published in 1914, but 

 the author's identity is now revealed. Most 

 books on map projection are either severely 

 mathematical or, at the other end of the scale, so 

 trivial as to have little value. Dr. Garnett strikes 

 a happy mean, and contrives to give within a 

 modest compass practically all that a student of 

 geography requires to know of this difficult sub- 

 ject. He wisely takes nothing for granted, and 

 as he develops his subject gives ample explana- 

 tion at each step. About half the book is con- 

 cerned with the principles involved, and the 

 remainder with the consideration of the principal 

 projections. The subject is treated with a fresh- 

 ness and lucidity which result in a most readable 

 book. The treatment of Sanson-Flamsteed's, MoU- 

 weide's, and Mercator's projections may be speci- 

 ally noted. There are a number of clear diagrams 

 and a short bibliography. The book should make 

 a strong appeal to teachers and students. 



Proceedings of the Aristotelian Society. New 

 Series, vol. xx. Containing the papers read 

 before the society during the forty-first 

 session, 1919-20. Pp. iv + 314. (London: 

 Williams and Norgate, 1920.) 255. net. 



The original papers included in this volume have 

 already been noticed in the reports of society 

 meetings. The present volume contains, in addi- 

 tion to the papers read at the ordinary meetings 

 of the society, two of the symposia contributed 

 to the Oxford Congress last September, in which 

 the members of the French Philosophical Society 

 took part. Of particular interest in this volume 

 is Prof. J. A. Smith's sympathetic account of the 

 philosophy of Giovanni Gentile, an Italian philo- 

 sopher, the originality of whose speculation, 

 already acknowledged in his own country, Is be- 

 ginning to be recognised universally. We may 

 also mention as of special scientific Interest Mr. 

 A. F. Shand's article on "Impulse, Emotion, and 

 Instinct," and Dr. Beatrice Edgell's article on 

 "Memory and Conation." The volume Is well up 

 to the high level of the proceedings of previous 

 years. 



