January 12, 1899] 



N^ TURE 



245 



He became laboratory assistant to Broca, and afterwards 

 one of his ablest disciples. He was always extremely 

 rich in modesty and poor in means ; spent his life un- 

 ostentatiously and contentedly plodding through a wilder- 

 ness of dry detail to gather a handful of generalisations 

 such as may he seen in this his last work. 



OUR BOOK SHELF. 

 An Experimental Course of Clieinistry for Agricultural 

 Students. By T. S. Dymond. Pp. 192. (London : 

 Edward Arnold.) 

 The attempt is often made to teach agricultural science 

 to students who have received no previous scientific 

 training ; the results of such an attempt are usually very 

 unsatisfactory. Agricultural problems are indeed highly 

 complex, and if the student is to understand the investi- 

 gations which have been made to solve them, and is 

 rightly to appreciate the results, he must be first ac- 

 quainted with the laws and facts of nature which are in- 

 volved in the phenomena under consideration. The 

 teaching of pure science must thus always precede the 

 teaching of applied science. Technical instruction given 

 alone, can only consist of a series of directions and pre- 

 scriptions, which are necessarily of very limited value. 

 As soon as a scientific e.xposition of the subject is 

 attempted, the preliminary study of pure science becomes 

 essential to success. 



The book before us is an introduction to chemical 

 science, intended for students who are about to study the 

 chemistry of agriculture. The course of instruction is 

 intended to be given in a chemical laboratory, and the 

 greater part of the experiments are to be performed by 

 the students themselves ; this is undoubtedly the best 

 way of learning a science. Mr. Dymond is much to be 

 congratulated on the very carefully constructed scheme 

 of work which he has now published ; its practical 

 merits are doubtless to a considerable degree due to the 

 fact, mentioned in the preface, that the scheme has been 

 in use during the past three years in many evening 

 schools and classes in the County of Essex ; the ideas of 

 the author have thus been gradually perfected by practice. 

 The course is intended as an introduction both to in- 

 organic and organic chemistry. The subjects selected for 

 the various lessons are, when possible, of an agricultural 

 character. Too much is sometimes attempted in this 

 direction. Subjects such as the physical properties of 

 soil, and the composition and properties of milk and 

 butter, fully deserve to be treated of in several lessons, 

 instead of the present brief notes in small type. The 

 two pages on the chemistry of animal and vegetable 

 life are a further example of the inadequate treatment of 

 subjects which really lie outside the scope of the prejent 

 course. Mr. Dymond would do well to write a second 

 course of instruction, to follow that which he has now 

 published ; in this the problems of agriculture could be 

 made the principal subjects of study. We can cordially 

 commend the book. R. W. 



Cesaintnelte Botanische Mittheilungen. Von S. Schwen- 

 dener. Two volumes. Pp. iv + 453 and 419. (Berlin : 

 (jebriider Borntraeger, iSgS.) 

 The last few years have seen the appearance of 

 " collected works " of more than one eminent German 

 botanist, and all students in the science will welcome the 

 newest addition to this form of literature. 



Truth to tell, Prof. Schwendener's work has hardly 

 met with the general recognition it deserves. Of course 

 every one is familiar with his relation to the lichen 

 controversy, and most of us have doubtless a more or 

 less intimate knowledge of his work on the ascent of sap. 

 Of his other writings, especially on physical matters 

 NO. 1524, VOL. 59] 



many have but a very scant acquaintance, and even the 

 anatomical papers are not as widely read as they deserve. 

 In a great measure this is no doubt due to the medium 

 which Dr. Schwendener commonly selected for publica- 

 tion, which prevented their free circulation amongst 

 fellow students ; but now they are rendered accessible, 

 they will assuredly command more attention at first 

 hand. For there is an immense amount of valuable 

 and interesting matter contained in the bulky volumes 

 before us, even though it is not always possible to follow 

 the author's meaning with ease, owing to his somewhat 

 difticult style. 



The papers are all accurate reprints (with the plates) 

 of the author's works which have been published since 

 1S79 ; l^ut where his views have undergone modification 

 since the appearance of any paper, readers will find his 

 present opinions stated in the appendices which are 

 added at the end of the text. 



As the papers have thus appeared for some time, it is 

 not necessary to discuss their contents here ; and it may 

 suffice to say that they deserve, and doubtless will obtain, 

 an honoured place in every botanical library. 



Die Be-wegung im Weltrauin. \'on E. Kethwisch. 

 Pp. 184. (Berlin: Schneider, 1896.) 



This book contains a criticism of the theory of universal 

 gravitation, although it does not deny that Newton 

 e-xplained the harmony of the universe with mathematical 

 exactness. A statement of a i^w of the conclusions at 

 which the author arrives, will probably suffice for the 

 readers of N.\Tl.'RE. 



According to the theory of gravitation the sun main- 

 tains the planets in their orbits ; but what is the force 

 that prevents the sun moving off into space ? The theory 

 demands some larger body which shall hold the sun, this 

 new body demands another, and so ad injiiiituiii. The 

 theory of gravitation is thus reduced to an absurdity. 



On p. 23 we learn that the number of oscillations of 

 a pendulum is quite independent of the force of gravity. 

 In fact, that theory demands that a heavy body shall 

 attract another with greater force the lighter is the latter. 



The attraction of Schehallien, as observed by Maske- 

 lyne, was due to magnetism ; and if Cavendish had made 

 his celebrated experiment with non-magnetic bodies, he 

 would not ha\e detected any attraction. 



The discovery of Neptune affords no proof of the 

 theory of gravitation. The received theory of the tide is 

 absurd, as lunar attraction cannot possibly cause the 

 semi-diurnal tide. The force of gravity on any planet is 

 wholly due to its rotation, and its intensity is directly pro- 

 portional to the linear velocity of a point on the equator. 



It is probable that this work contains many other 

 remarkable propositions ; but the writer of this notice 

 did not read to the end. 



Small Accumulators. How Made and Used. Edited by 

 Percival Marshall. Pp. 62. (London : Dawbarn and 

 Ward, Ltd.) 



This is the first of a series of small and popular scientific 

 manuals for amateur electricians and students. The 

 instructions are sufficient to enable small accumulators 

 to be constructed by readers who have not any previous 

 knowledge of electricity ; and for readers who prefer to 

 purchase these appliances, descriptions are given of 

 several forms of storage battery. 



Natalite ei Democratic. By A. Dumont. Pp. 230. 

 (Paris: Schleicher Fr&res, 1898.) 



The six lectures printed in this volume were delivered at 

 the Paris Ecole d'anthropologie during the session 1S96- 

 97. They are all concerned with the subject of de- 

 population in France, variations of the birth-rate in 

 different districts, and the importance of the effects upon 

 national welfare. 



