March 27, 1919] 



NATURE 



63 



tails him Mr. Hendrick is by no means averse to 

 calling- in the aid of rhyme. 



On the purely theoretical side Mr. Hendrick 's 

 treatment of the subject is scarcely so satisfactory. 

 It is very doubtful if a beginner would be much 

 wiser about the ionic theory after reading 

 pp. 22-25; and the description of the origin of 

 stereochemistry on pp. 244-45 scarcely does van't 

 Hoff justice, whilst Le Bel is not even mentioned 

 in that connection. 



At the present time, when it seems necessary 

 ^ that the general public should appreciate what 

 chemistry does for them, even if they cannot 

 understand how it does it, Mr. Hendrick's book 

 should play a very useful part; and it is to be 

 hoped that the demand for it among laymen will 

 be a large one. Admitting the limitation which 

 the author imposed upon himself, there can be 

 no doubt that the book is excellent. 



OVR BOOKSHELF. 



Hygiene of the Eye. By Dr. W. Campbell 

 Posey. Pp. x + 344. (Philadelphia and Lon- 

 don: J. B. Lippincott Co., 1918.) Price 185. 

 net. 

 It is a good sign that ever greater attention is 

 being directed to preventive medicine, for pre- 

 vention is better than cure. The proverb is speci- 

 ally apposite when applied to many disorders of 

 the visual apparatus. A sound treatise on the 

 hygiene of the eye is badly wanted — or, rather, it 

 should be said, two such works are to be desired, 

 one for ophthalmologists, and one for the general 

 public. Dr. Posey's work fails to meet either 

 requirement satisfactorily, for it falls between two 

 stools. The chapters on the structure of the eye 

 ; and on diseases of the eye are too elementary for 

 the ophthalmologist, and scarcely intelligible 

 to the layman. Moreover, the considerable space 

 allotted to many diseases of which we do not 

 know the causes, or are unable to prevent them, 

 might have been better utilised in expanding parts 

 more nearly related to what is commonly under- 

 stood by the term "hygiene." The chapter — by 

 the author — on school life is particularly good, 

 and the same may be said of the chapters on 

 artificial illumination (by Dr. Herbert E. Ives) 

 J and on daylight illumination (by Mr. W. C. 

 Farber, an architect). These subjects would have 

 borne further elaboration. 



The author's chapters on conjunctivitis and the 

 preventive measures to be adopted against con- 

 tagion, and on wounds and injuries of the eye, 

 are admirable. The chief industrial injuries are 

 described, and the means of protection against 

 them' are illustrated by good photographs. There 

 is a most interesting chapter on blindness from an 

 economic and social point of view, and on the 

 education and employment of the blind, by Mr. 

 O. H. Burritt, principal of the Pennsylvania In- 

 stitution for the Instruction of the Blind. 



Dr. Posey is a safe guide, though he makes 

 some dogmatic statements with which all ophthal- 

 mologists would not agree. AVe hope that a 



NO. 2578, VOL. 103] 



second edition will give him the opportunity of 

 eliminating irrelevant material and expanding 

 those parts which are more in accord with the 

 title. 



Elements of General Science. By Prof. Otis 

 William Caldwell and Prof. William Lewis 

 Eikenberry. Revised edition. Pp. xii + 404. 

 (London: Ginn and Co., 1918.) Price 55. 6d. 

 net. 



Those who are interested in the teaching of 

 natural science are already familiar with the 

 publications of Messrs. Ginn and Co. in con- 

 nection with the elementary and general treat- 

 ment of the subject. The " Elements of General 

 Science," by Profs. Caldwell and Eikenberry, 

 rapidly found favour in England among the many 

 who were growing dissatisfied with the dry and 

 formal teaching which has been all too common. 

 The authors succeeded in being simple without 

 being superficial, and, with the help of the pub- 

 lishers, in producing a book which can be read 

 with pleasure as well as with profit — a point which 

 is so often overlooked. 



The revised edition, which has been largely re- 

 written, is much bigger than the original one. 

 Electricity and magnetism have now been in- 

 cluded. In the forty-eight pages devoted to these 

 subjects there are to be found figures of lighting- 

 circuits, watt-hour meters, motor-car circuits, 

 telephones, and transformers. Another thirty-five 

 pages have been given to astronomy, with a 

 series of excellent figures. The problems of nutri- 

 tion and of food have received additional atten- 

 tion, and it is entirely in keeping with the spirit 

 in which the book is written that five excellent 

 charts have been prepared showing the relative 

 costs of equivalent food-values of different things. 

 In this, as in many other ways, the relations 

 between the studies and the problems of every- 

 day life have been kept prominently in view. The 

 teacher who uses this book is not likely to be 

 bothered by the question, "What is the use of 

 learning this? " And yet the authors cannot be 

 accused of having neglected true education in the 

 effort to interest or amuse. 



The Year-book of the Scientific and Learned 

 Societies of Great Britain and Ireland. Com- 

 piled from Official Sources. Pp. viii + 333. 

 (London: Charles Griffin and Co., Ltd., 1918.) 

 Price 95. net. - 



The present is the thirty-fifth annual issue 

 of this very useful work of reference. Twenty-six 

 societies not previously included appear in this 

 edition, and the claims of music to be numbered 

 among the learned societies have been recognised. 

 The compilation constitutes a record of the work 

 done in science, literature, and art during the 

 session 19 17-18 by the various societies and 

 Government institutions, and deserves an import- 

 ant place among the reference books of workers 

 in science. The arrangement and method of in- 

 dexing adopted make reference to the contents 

 easv. 



