August 21, 1913J 



NATURE 



6m 



or at least some of them, are decomposition-pro- 

 ducts of proteins, chlorophyll, and other complex 

 substances. As regards their function in the 

 plants, they have been variously considered as 

 nutrient materials, protective substances, or end- 

 products of metabolism, rendered harmless to the 

 plant, and stored chiefly in special cells whence 

 they are not readily re-absorbed into the active 

 plant tissues. 



On these and other general questions Dr. 

 Henry touches, though but lightly, in the intro- 

 duction to the work under review. It is rather 

 a pity that more space was not given to this 

 aspect of the subject : the one criticism which the 

 book invites is that it is too much like a collection 

 of extracts from the Journal of the Chemical 

 Society. But it is a good collection, and includes 

 the chief historical, chemical, physical, and 

 physiological data relating to the numerous 

 alkaloids dealt with ; whilst in the case of those 

 which have been successfully studied, a concise 

 summary is given of the experimental evidence, 

 and of the arguments founded on this evidence, 

 which elucidate their structure and establish their 

 accepted chemical formula;. In particular, readers 

 whose business or pleasure it is to study the less- 

 known alkaloids will often be moved to call down 

 a benediction on the head of the author. 



C. Simmokds. 



RECENT BOOKS ON PHYSICS. 



(1) Introductory Electricity and Magnetism. By 

 Carl W. Hansel. Pp. xv + 373. (London: W. 

 Heinemann, 1913.) Price 25. 6d. net. 



(2) Mathematical Physics. Vol. i. Electricity 

 and Magnetism. By C. W. C. Barlow. Pp. 

 vii + 312. (London: W. B. Clive, 1913.) 

 Price 4s. 6d. 



(3) La Matiere : Sa Vie et ses Transformations. 

 By Prof. Louis Houllevigue. Preface de Ed. 

 Bout'y. Pp. xxxii + 318. (Paris: Librairie 

 Armand Colin, 1913.) P.rice 3.50 francs. 



(4) Dispersion und Absorption des Liclites in 

 ruhenden isotropen Korpern. Theorie und 

 ihre Folgerungen. By Dr. D. A. Goldhammer. 

 Pp. vi+144. (Leipzig and Berlin: B. G. 

 Teubner, 1913.) Price 3.60 marks. 



(3) Cours de Physique Generate. Lecons pro- 

 fessees a la Faculte des Sciences de l'Universite 

 de Lille. By H. Ollivier. Tome Second. 

 Thermodynamique et Etude de l'Energie Rayon- 

 nante. Pp. 295. (Paris : A. Hermann et Fils, 

 1913.) Price 10 francs. 

 (1) ' I "HIS book is intended for beginners, but 

 _1 covers the syllabus of the lower certifi- 

 cate examination of the Board of Education. The 

 order of treatment adopted is : — magnetism, elec- 

 NO. 2286, VOL. 91] 



trostatics, current electricity. Each branch is 

 introduced by a simple qualitative account before 

 the more advanced quantitative aspects are con- 

 sidered. 



The treatment of the electrostatics is most lucid, 

 and the author makes, and rightly, a special plea 

 for more experimental work, performed by the 

 student himself, in this part of the subject. A 

 number of qualitative experiments are suggested, 

 several of which could be made roughly quantita- 

 tive, even without the spherical condenser, charged 

 to a known potential, which Mr. Hansel desires 

 installed in every laboratory. 



There is very little fault to be found : too much 

 stress is laid on the experimental verification of 

 the inverse square law with verv long magnets ; 

 an elementary account of the Cavendish proof of 

 the same law should be given in electrostatics, and 

 an account of the kathode rays and allied pheno- 

 mena would increase the utility of the book for 

 many students. 



Each chapter contains a number of questions, 

 the numerical answers being given at the end. 

 The diagrams, if in some cases rather crude, are 

 clear, and have not been stinted. Anyone seek- 

 ing a class-book in elementary electricity will 

 scarcely better this. 



(2) A complete account of the subject to the 

 standard of the pass degree is given in this, the 

 latest issue from the University Tutorial Press; 

 but the descriptive portions are necessarily re- 

 duced to the mere outline required to make the 

 mathematics intelligible. Selected portions will 

 be found helpful by all preparing for examinations 

 in electricity, whether of intermediate or honours 

 standard. 



The author's aim is to equip the man already 

 familiar with the elements, so that he may read 

 the advanced treatises with understanding, and 

 at the same time to give him that precision of 

 thought which can only be obtained by working 

 numerical examples. The mathematics involved 

 is of a very simple character, a very slight know- 

 ledee of the calculus being required for the 

 chapters on condensers and induced currents. 



The last chapter contains a summary of the 

 corpuscular theory, marred by one unfortunate 

 statement. On p. 296 we find : " Practically the 

 whole inertia of the atom is supposed to belong 

 to its negative corpuscles. Of these there are 

 roughly 1800 in the case of a hydrogen atom." 

 Later : " These ideas must not be regarded as 

 facts." True, but they should at least represent 

 the current notions of the subject. 



(3) Prof. Houllevigue has collected under this 

 title a set of twelve essays dealing, in a semi- 

 popular fashion, with some modern aspects of 



