276 



\ VI ORE 



[December 28, 191 1 



the experiment* lo be continued on the Mine plot* 

 lor a period of not less than ten years. If this were 

 done at. say, 500 to 1000 centres, we venture to think 

 that a vast step forward would be made; the inter- 

 p, uion of ihr figures of soil'analysis would become 

 prtciso than it is at present, and the relationship 

 botw.tn soil texture and com|>osition and its produc- 

 tive power or capacity to grow crops would be more 

 clearly understood. J* P- 



OUR BOOK SHELF. 



An Accow ■ ' ■' ■ Crustacea oj Horway. By Prof. 

 G. O. Is. i.-v. Vol. v., Copt'poda Har- 



pacticoiiii. i I'. 449 + 2S4 plates. (Bergen: Pub- 

 lished by the Ikrjjen Museum, 1890-191 1.) 

 By the publication of the concluding parts of vol. v., 

 Prof. Sars has now provided us with the first adequate 

 account of the harpacticoid Copepoda. It was per- 

 haps natural that pelagic Copepoda should first attract 

 the attention of investigators, but many zoologists 

 still appear to think that such forms constitute the 

 principal representatives of the group. This is by no 

 means the case, but perhaps on account of this 

 erroneous impression, the llarpacticoida and other 

 bottom forms have been very much neglected. 



An examination of the present volume at once sug- 

 gests that we still have much to learn of this interest- 

 mg assenitil.iL^i'. ihe author gives descriptions of no 

 fewer than .-'ii -p.rK s belonging to 99 genera, but at 

 the same time h. !• 11^ us in his preface that his latest 

 excursion in the summer of 1910 produced about forty 

 additional species, many of them new to science, and 

 most of them obtained in a single locality. This is 

 sufficient evidence that a great deal yet remains to 

 be done, and indeed it is only on the British coast, in 

 addition to that of Scandinavia, that the true bottom 

 forms have been seriously studied, in spite of their 

 considerable economic importance. 



It is a matter of some satisfaction that countrymen 

 of our own are among the foremost authorities quoted 

 by Prof. Sars, but this is primarily an indication that 

 these particular forms have been little investigated 

 elsewhere. The abundant large-scale drawings which 

 illustrate each species afTord in themselves a most 

 trustworthy means of identification, and it is to be 

 hoped that with such a convenient book of reference 

 now available, a much more extended survey of the 

 types tivintr on the sea bottom will be attempted. \\V 

 conjLriatuI.itr the veteran author on the successful com- 

 pletion of anofhor volume, and the scientific public on 

 the steady ^mwth of this very valuable work. 



W. A. CUNNINCTON. 



TraiH de Chimic Ccndrale. By Prof. W. Nemst. 

 Ouvrage traduit sur la 6« Edition allemande par 

 Prof. A. Corvisy. Deuxi^me Partie, "Transforma- 

 tions de la Mati^re et de I'Energie." Pp. 422. 

 (Paris : A. Herman et Fils, 1912.) Price 10 francs. 

 The issue of the translation in two parts is to be 

 commended, for the original has grown to such an 

 extent in passing through its six editions that a 

 single volume would be of inconvenient dimensions. 

 It is only quite recently that an English version, 

 revised in accordance with the sixth German edition, 

 made its appearance, and was reviewed in these 

 columns. In these circumstances, it need onlv be 

 said in reference to the general character of the "book 

 that the translator's work in the second volume is of 

 the same high standard as that attained in vol. i. 



With regard to the treatment of the subject-matter, 

 attention may be directed to the question of catalvsis. 

 In explanation of the general catalytic activitv of 

 NO. 2200, VOL. 88] 



acids it is assumed, as usual, that the active agents 

 are the free hydrogen ions. It is true that many of 

 the older observations relating to the catalytic activity 

 of acids can be accounted for on this theory if certain 

 subsidiary hypotheses are accepted, but this apparent 

 harmony between theory and experiment vanishes as 

 soon as we leave the domain of aqueous solutions. 

 Recent work has indeed shown that the catalytic 

 activity of acids in non-ionising solvents is much 

 greater than in aqueous or other ionising media, and 

 this important fact cannot be reconciled with the 

 usual ionic explanatk>n of acid catalysis. In view of 

 the importance of the question, the lack of any r< t i - 

 ence to such observations must be regarded a-» .. 

 serious omission in a treatise which, in so many other 

 respects, may be considered as efficiently revised in 

 accordance with the progress of physico-chemical 

 science. 



In regard to the much-discussed question of the 

 nature of crystalline liquids, the author gives an excel- 

 lent short summary, but considers that none of the 

 theories advanced can be harmonised with experi- 

 mental observations. 



Three short notes are added by the translator 

 dealing respectively with (i) the direct measurement of 

 osmotic pressure by Fouard's method; (2) the radio- 

 active elements ; and (3) the methods of measurinti 

 the number of molecules in the molecular volume. 



Text-hook oj Mechanics. By Prof. L. A. Martin, jun. 

 Vol. iii., "Mechanics of .Materials." Pp. xiii + 229. 

 (New York : John VV^iley and Sons ; London : Chap- 

 man and Hall, Ltd., 191 1.) Price 1.50 dollars net. 

 The present volume forms the third of a series, the 

 first dealing with statics and the second with kine- 

 matics and kinetics, having been reviewed in Nature 

 of May 16, 1907, and February 6, 1908, respectively. 

 The author has not attempted to treat the mechanics 

 of materials exhaustively ; the matter includes simple 

 stresses and strains ; the strength and elasticity of 

 beams ; statically indeterminate beams ; struts and 

 columns ; torsion ; general theorems of stress and 

 strain ; compound stresses ; the principle of work as 

 used in computing deflections. 



The calculus has been used freely, and the impres- 

 sion is given to the reader that there has been a 

 straining after mathematical effect, instead of the 

 mathematics employed being made subordinate to the 

 clear expounding of the mechanical principles in- 

 volved. Illustrations have been taken, not because of 

 their practical importance, or of their service in 

 elucidating the subject, but because " they furnish 

 interesting applications of the calculus." We note 

 the very scanty use made of the ellipse of stress, 

 although by means of this method much shorter and 

 more readily comprehended solutions may be obtained 

 in many cases. The same straining after mathe- 

 matical effe_ct may be observed in the treatment of 

 thin cylindrical and spherical shells under internal 

 pressure. Methods of testing and experimental 

 results are almost absent, an omission which helps 

 to contribute to the air of unreality in the treatment. 



Some minor blemishes occur ; in finding and using 

 a formula for the horse-power traflktnrtted by shafting, 

 the reader is not warned that the torque must be 

 uniform — a state of affairs which scarcely ever occurs. 

 The "dangerous section " of a beam is defined as that 

 at which maximum bending moment occurs ; this will 

 be the case in some instances, but a better and more 

 general definition would be that section which has 

 maximum stress. The book has clear diagrams, and 

 numerous, well-considered exercises for working out 

 are included, a point which will recommend the 

 volume to uiany students. 



