June 21, 19 17] 



NATURE 



323 



of all ages will have been aroused ; he will, no 

 doubt, have drawn from the portraits in the book 

 very vivid and characteristic conclusions as to 

 the j>ersonal app)earance of men like Klein, 

 Fermat, and Gauss ; and, being a lucky American 

 boy, his interest will have carried him yet further 

 to the biographies in the school library. If this 

 is indeed his gain, it is no small acquisition. In 

 most cases it is to be hoped that he will have 

 learned to dispense with the irritating "Why?" 

 which peppers the pages with the doubtful 

 stimulus of a confession of weakness. 



{3) Prof. Barnard's volume is very straight- 

 forward and is clearly written. The difficulties 

 of beginners are not unknown to him, and in the 

 selection and construction of examples he claims 

 to have borne in mind the advantage of extensive 

 numerical applications and the necessity of con- 

 stant appeal to fundamental principles. From 

 the outset he brings in the use of limits " as the 

 only satisfactory way of defining such quantities 

 as velocity and acceleration." The advantages of 

 vector analysis are very much in the (Australian) 

 air at the moment, so we have a chapter on the 

 "merest beginnings" of the elements, which i^ 

 to be regarded as giving " an alternative method 

 of dealing with questions connected with parallelo- 

 gram laws." The value of what may be called a 

 merely incidental reference to the use of a power- 

 ful tool may be questioned. "O the little more 

 and how much it is ! " The direct treatment of 

 simple harmonic motion as rectilinear motion 

 under a given law of force is justified by the 

 statement that "it has the advantage that the 

 student is not led to imagine that some sp>ecial 

 circle has to be thought of in connection with the 

 motion, as is so commonly the case in the com- 

 mon method." About one-fifth of the book is 

 devoted to rigid dynamics. Altogether it is a 

 very interesting endeavour to smooth the path of 

 the beginner who is to continue his study of the 

 subject when provided with the additional weapon 

 afforded by the calculus. W. J. G. 



OUR BOOKSHELF. 



The Advanced Atlas of Physical and Political 

 Geography. A New Series of Maps Specially 

 Designed for Schools, Colleges, and Private 

 Students. By Dr. J. G. Bartholomew. Pp. 

 96 + 31. (London: Oxford University Press, 

 1917.) Price 85. 6d. net. 



At last a British firm has supplied the atlas for 

 I which colleges and universities have been asking 



for years. For anything between school work 



and a general reference atlas it used to be neces- 

 I sary to go to Germany. The firm of Bartholomew 

 I has now produced something far better than a 

 I German atlas, and at a price that would be low 

 j even in peace-time. Both in its plan and in its 

 j execution the atlas is excellent and is deserving 

 i of all praise as the best atlas of its kind that has 



been published. There are ninety-six plates of 

 XO. 2486, VOL. 99] 



maps, each plate 13^ in. by 8^ in., and a full 

 index of names. Most plates contain plans and inset 

 maps, and all are printed in colours. Every country 

 is shown by an orographical map, which contains 

 also political frontiers, railways, and a consider- 

 able number of names. A few countries have 

 separate political maps in addition. All the oro- 

 graphical maps are layer-coloured in brown and 

 green. There are, in addition, vegetation, rain- 

 fall, temperature, and population maps for each 

 continent. The fineness of the workmanship and 

 the excellence of the colour-printing are note- 

 worthy and maintain the high reputation of the 

 Edinburgh Geographical Institute. The geological 

 map of Europe and the orographical maps of 

 Ireland and of France with Belgium are three 

 specially fine examples of cartography. Among 

 other features of this atlas it should be noted that 

 the projections of all the chief maps are given, 

 and that there are two plates illustrating projec- 

 tions. The countries of Europe are shown on 

 scales varying from i : 1,700,000 to i : 5,000,000, 

 except Russia, which is on a somewhat small 

 scale. It is an atlas that will do much to promote 

 the very necessary extension of ereographical 

 teaching which must be the immediate concern 

 of this country. R. N. R. B. 



Food and Fitness : or Diet in Relation to Health. 



By James Long. Pp. ix + 208. (London : 



Chapman and Hall, Ltd., 1917.) Price 55. 



net. 

 This book possesses a topical interest at the 

 present time, inasmuch as it deals particularly 

 with vegetable foods, giving details of their 

 energy-values and cost at pre-war prices. 

 Although the author states that he is not a 

 vegetarian, the purport of the book is an ad- 

 vocacy of vegetarian principles in diet. It is 

 remarked that the knowledge displayed by owners 

 of stock regarding the proper feeding of their 

 animals is much more profound than that which 

 applies to themselves, which is very true. An 

 excellent chapter deals with the most economical 

 foodstuffs, and the cereals and pulses easily take 

 the first place. The author pleads with justice 

 for an increase in vegetable foods and a decrease 

 in animal ones as age advances and for economy, 

 and the qualities and characters of the principal 

 vegetables and fruits are described, together with 

 suggestions on serv'ing and cooking them. 



A chapter on the selection of foods, including 

 animal foods, gives many valuable hints, and 

 another gives records of weights of food before 

 and after cooking. Finally, some useful sugges- 

 tions are given on sleep and how to attain it, and 

 tables of energy-values of the principal food- 

 stuffs per penny cost complete the volume. 

 While the author's advocacy occasionally leads 

 him to make statements which are not entirely 

 correct, the book as a whole contains a great deal 

 of sound and useful information, and the caterer 

 and housewife who wish to economise will glean 

 from it many valuable suggestions. 



