July 17, 19 13] 



NATURE 



501 



aerobic and anaerobic decompositions proved en- 

 tirely too much for the author : — 



" Curiously enough, he says, " some scientists 

 say that if air is admitted to the soil nitrogen is 

 set free from the organic matter ; and, on the 

 other hand, if air is excluded, nitrogen is set free 

 from the nitrates ; and in both cases it is lost. 

 These views would appear to be mutually destruc- 

 tive." 



The chemist is still worse : when appealed 

 to by growers to help in checking plant-diseases, 



"the chemist, like a sensible man of business, 

 immediately proceeded to compound his nostrums 

 and to talk learnedly about the fungoid and other 

 diseases, at the same time not forgetting to take 

 the fees to recompense him for his learning and 

 skill." 



But perhaps the most severe treatment is reserved 

 for Rothamsted. 



" The cultivation seems to be of the poorest 

 description ; in fact, it can hardly be described as 

 cultivation at all. . . . One can imagine the con- 

 dition of the soil ... it must be almost as hard 

 as rock, and impervious to rain, air, or roots. . . . 

 Farming on the Rothamsted principle would 

 appear to be a very precarious business." 



As all this occurs in a science section, first-hand 

 information was apparently deemed superfluous ; 

 nevertheless, a visit to Rothamsted first of all 

 might not have been a bad idea. After this we 

 are quite prepared for the author's scheme for 

 making the wheat crop yield a profit of more than 

 70?. per acre, instead of 4/. or less as at present. 

 The experimental basis consists of a trial made at 

 Ealing in 1910 with 400 seeds; the results are 

 multiplied up till they can be expressed in terms 

 of one acre; and this in turn is multiplied up 

 till the author foresees that "thousands of men 

 would be kept on the land at better wages, and 

 our wheat crops would be increased enormously. 

 Agriculturists would do well to consider the 

 above figures before smiling too broadly at them. " 

 Unfortunately, agriculturists have had these 

 paper schemes presented to them fairly often for 

 at least 250 years past, and now they require facts. 

 Enough has been said, however, to show the sort 

 of "science" that is considered good enough for 

 growers. E. J. Russell. 



TEXT-BOOKS OF PHYSICS. 



(1) Experimental Mechanics and Physics. By 

 A. H. E. Norris. Pp. viii+176. (London: 

 Mills and Boon, Ltd., n.d.) Price is. 6d. 



(2) Elementary Physical Optics. By W. E. 

 Cross. Pp. 312. (Oxford: Clarendon Press, 

 1913.) Price 3s. 6d. 



(3) Heat: A Manual for Technical and Industrial 



NO. 2 28l, VOL. Ql! 



Students. By J. A. Randall. Pp. xiv + 331. 

 (New York: John Wiley and Sons; London: 

 Chapman and Hall, Ltd., 1913.) Price 6s. 6d. 

 net. 



(4) A Synopsis of the Elementary Theory of Heat 

 and Heat Engines. By J. Case. Pp. iii + 65. 

 (Cambridge: W. Heffer and Sons, Ltd., 1913.) 

 Price 2S. 6d. net. 



(5) Elementary Principles of Electricity and Mag- 

 netism for Students in Engineering. By Dr. 

 R. H. Hough and Dr.'w. M. Boehm. Pp. 

 vii + 233. (New York: The Macmillan Com- 

 pany; London : Macmillan and Co., Ltd., 1913.) 

 Price 6s. 



(6) Transport de Force. Calculs Techniques et 

 Economiques des Lignes de Transport et de 

 Distribution d'Energie Electrique. By C. Le 

 Roy. Deuxieme Partie. Pp. 143. (Paris : 

 A Hermann et Fils, 1913.) Price 6 francs. 



(7) First Year Course in General Science: A Com- 

 bined Text-book and Note-book. By E. A. 

 Gardiner. Pp. vi+113. (London: W. Heine- 

 mann, n.d.) Price 2s. 6d. net. 



(1) ' I ^HE title of this little book is rather mis- 

 L leading. The use of the word " physics " 

 suggests that the contents of the book comprise 

 the various branches of physics, and not merely — 

 as is actually the case— heat and a meagre treat- 

 ment of a few of the properties of matter. These 

 subjects occupy only one quarter of the volume, 

 the remainder being devoted to mechanics. The 

 treatment is very simple and is suitable as an 

 introductory course. In this respect the book will 

 no doubt serve its purpose as efficiently as many 

 others of its class, although it exhibits no note- 

 worthy advances in the mode of presentation of 

 the subject. The frequent change of type is rather 

 an unfortunate feature, and some of the diagrams 

 are very badly drawn, notably a cube used to 

 represent the measurement of volume, the per- 

 spective of which is in exactly the wrong sense. 



(2) This book has several very good points. 

 The subject is treated in a straightforward and 

 lucid manner. The author has endeavoured to 

 develop the theory of optics upon both " ray " 

 and "wave" bases simultaneously, and we think 

 he has succeeded. There is much to be said for 

 both methods of treatment, and neither should 

 be ignored. As is natural in an elementary treat- 

 ise, no very difficult problems are considered, but 

 it is rather surprising to find practically no refer- 

 ence to diffraction and interference, especially as 

 some stress is laid on the wave theory. There are 

 many simple experiments in this connection which, 

 far from confusing a junior student, would un- 

 doubtedly interest him. One of the most notable 



