August \ 



1889] 



NATURE 



17 



in the influence they exercise on the thought and memory 

 of him who compiles them, yet it is impossible to ignore 

 the fact that, in these days of many examinations, there 

 is a persistent demand for works of the class. It is well, 

 therefore, that books of the kind should be prepared with 

 reasonable intelligence, and with such care against the 

 propagation of glaring and misleading errors as the 

 author of this work has certainly shown. It would un- 

 doubtedly be better that the teachers should prepare their 

 own lecture-notes, with illustrations derived from per- 

 sonal reading and study ; and no less desirable is it that 

 the taught should make such notes of the facts referred 

 to in illustration of the lessons given them, as to be able 

 to recall to their minds the arguments of the teacher, and 

 the principles which he has aimed at enforcing. For 

 teachers and students who are incapable of following this 

 very obvious and desirable method, however, notes and 

 tables of the kind before us certainly have their use. 

 Mr. Gwinnell's book is happily free from the gross absurdi- 

 ties and mistakes so common in many of the books pre- 

 pared with the avowed aim of meeting the wants of those 

 preparing for examination ; and, for those who must 

 have a crutch, we may admit that this is a very excellent 

 one of its kind. We have noticed a few unfortunate errors, 

 such as the statement that granitite contains pink ortho- 

 clase, and that graphic granite consists of " quartz and 

 felspar arranged in lines like writing." The pretty geo- 

 logical map of Great Britain forming the frontispiece, 

 too, which has been adopted from a work that appeared 

 a good many years ago, exhibits nearly the whole of the 

 Scottish Highlands as consisting of Lower Silurian rocks. 

 On the whole, however, the book has the merit of being 

 accurate and up to date, and the author is entitled to the 

 praise of having very carefully selected, arranged, and 

 verified the mass of miscellaneous information which he 

 has brought together. 



La Pdriode Glaciare : Etiidii^e principalement en France 

 ct en Suisse. Par A. Falsan. (Paris : Felix Alcan, 

 1889.) 



This volume, which is the most recent addition to the 

 collection of the " International Scientific Series," pub- 

 lished in the French language, contains a most admirable 

 resume of facts and opinions bearing upon the Glacial 

 period, as illustrated in France and Switzerland. The 

 author shows a very extensive acquaintance with the im- 

 mense body of literature dealing with glacial questions, 

 by English, American, German, and Scandinavian geolo- 

 gists ; and very fairly and temperately discusses the bear- 

 ings of the numerous theories that have been put forward 

 upon the facts observed in France. As the references to 

 original memoirs are very full and complete, the work 

 cannot fail to be of much value to glacialists and geolo- 

 gists in general, while it admirably fulfils its main object, 

 that of giving an accurate and popular account of the 

 current knowledge and opinion of geologists upon glacial 

 questions, especially adapted to the want of French 

 readers. 



Even when compelled to express his dissent from ex- 

 treme views upon such questions as the recurrence of 

 glacial periods in past geological times, the influence of 

 glaciers in excavating lake basins, and the existence of 

 man in Tertiary times, M. Falsan clearly states the 

 grounds on which conclusions different from his own I 

 have been arrived at by other authors. In his presenta- ' 

 tion of the arguments for and against the various glacial 

 theories, his moderation and his fairness are alike 

 conspicuous. 



The author of this book has taken an active part in the 

 important work of preserving the most conspicuous of the 

 fine boulders scattered over France ; and numerous sketches 

 of these boulders, with many interesting details concern- 

 ing them, find a place in these pages. Two plates, a map 

 showing the former extension of the French glaciers, and 



a series of sections illustrating the former dimensions of 

 the Rhone Glacier, accompany the work ; but the other 

 j engravings are wanting in the beauty and finish so often 

 found in books published in France. The very full table 

 of contents does not compensate for the total absence of 

 an index to the book. 



Physiological Diagrams. With an Index. By G. Davies. 

 (Edinburgh and London: W. and A. K.Johnston, 1889 ) 



These diagrams are designed for use in schools, and to 

 "supply the teacher with a means (by teaching the pupils 

 to draw from them) of impressing the form and organs of 

 the different parts of the body on vhe pupils' minds." There 

 are nine in all (each 22 X 30) printed in black upon card- 

 board, with eyelet holes for hanging purposes. The parts 

 are represented in hard outline, each being numbered, in 

 accordance with a series of explanatory reproductions in 

 miniature, which accompany the " text." The whole pro- 

 du::tion is most feeble. It is only when the author relies 

 upon standard works that his diagrams are tolerable, and 

 his only really useful sheet (No. i) is a copy. Seeing that 

 much better wall diagrams have long been before the 

 public, we are at a loss to see any raison d'etre for these 

 poor apologies. We are told that *' the principal object of 

 these drawings is to facilitate the teaching of physiology 

 in schools." So much the worse for the schools ! We 

 cannot congratulate either author or publishers upon 

 their venture. The day is past in which anything in 

 outline will pass current for an atlas ; and pictorial aids 

 to the teaching of elementary physiology, to be of any 

 service, must be produced by competent authorities. 



Woolwich Mathematical Papers, 1880-88. Edited by E. 

 J. Brooksmith, B.A., LL.M. (London: Macmillan 

 and Co., 1889.) 



In this book we have a collection of the various papers 

 in mathematics prepared during the last eight years to 

 test the knowledge of candidates for admission into the 

 Royal Military Academy. The subjects are : geometry, 

 arithmetic, algebra, plane trigonometry, statics, and dy- 

 namics. The volume will prove most useful to those 

 who intend entering for these examinations, and will 

 also be of service to many teachers in our public and 

 private schools. The answers to the examples in the 

 various papers are collected together at the end. 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications. ] 



Head Growth in Students at the University of Cambridge. 



Under the above heading there appeared in Nature, vol. 

 xxxviii, p. 14, an article in which certain very weighty con- 

 clusions are drawn from grounds which I hope to show are 

 quite inadequate. These conclusions are as follow : — 



(i) Although it is pretty well ascertained that in the masses of 

 the population the brain ceases to grow after the age of 19, or 

 even earlier, it is by no means so with University students, 



(2) That men who obtain high honours have had considerably 

 larger brains than others at the age of 19. 



(3) That they have larger brains than others, but not to the 

 same extent, at the age of 25 ; in fact, their predominance is by 

 that time diminished to one-half of what it was. 



(4) Consequently "high honour" men are presumably, as a 

 class, both more precjcious and more gifted throughout than 

 others. 



These conclusions were deduced from measurements taken in 

 the following way. The maximum length, width, and height 

 (above a specified plane) of the head are taken in inches and 

 decimals of an inch. . Since the quantities lie between 5 and 8 



