246 



NATURE 



[July 15, 1897 



unnecessary iteration. This repetition, it is true, is apolo- 

 gised for in the preface, but it could have been avoided 

 by altering the plan of the book, which as it stands is 

 rather confusing. 



What strikes one most on glancing through the pages 

 is the disproportionate treatment of the subject. To 

 devote one-third of the whole book to the mammalian 

 skeleton shows that the author has allowed himself a free 

 hand where the facilities for compilation are greatest — 

 and his indebtedness to the " Osteology of the Mammalia" 

 is admitted in the preface. Where, however, it has been 

 necessary to collect the detailed statements from scattered 

 sources, as, for instance, in Fishes and Amphibia, the 

 results are very far fi'om satisfactory. The parts relating 

 to the Cyclostomi, Ganoid fishes, the shoulder-girdle of 

 Anura, and the hyoid of Reptilia are especially poor. The 

 classifactory scheme (pp. 30-49), including as it does 

 extinct as well as living vertebrates, should prove of con- 

 siderable service to the student. It is well up to date, 

 and, on the whole, trustworthy, although ichthyologists 

 will probably gird at the inclusion of a physoclistous 

 form like Exoccetus among the Clupeidae. It would 

 have been well if the generic and specific names of the 

 borrowed figures had been checked by reference to some 

 modern catalogue, instead of relying so implicitly upon 

 those used by the original authors. Galeus, for instance 

 (Fig. 15), should read Galeocerdo, and Docidophryne 

 i^igantea (Fig. 30), Btifo marinusj while the Figs. 16 and 

 17 of the seven-gilled shark should, in the student's 

 interests, be given the same generic name, either 

 Notidanus or Heptanchiis. The specimen in the Natural 

 History Museum, on which Fig. 16 is based, is marked 

 Notidanus, while Gegenbaur's figure, which is repro- 

 duced in Fig. 17, is labelled Heptanc/ms, and Mr. 

 Reynolds has, regardless of uniformity, adopted the two 

 names as he found them. 



The want of cohesion throughout the text detracts 

 seriously from the value of the book. The various sec- 

 tions, culled from different sources, are not blended 

 together, so that the product is indigestible and difficult 

 of assimilation. The failure to treat the subject from a 

 consistent morphological point of view is, in fact, the 

 great flaw in the book. Positive inaccuracies are not com- 

 mon, but the sternum ought not to come under the head 

 "Hyoid apparatus" (p. 162), the epipubic cartilage of 

 Xcnopus (p. 188) and the horny beaks of Siren (p. 168) 

 are not " minute," and auditory ossicles are not as large 

 as Fig. 100 would lead one to believe. The application 

 of the name "branchiostegal rays" to the endoskeletal 

 cartilages of the branchial septum of selachians (p. 120) 

 implies a false homology with the dermal bones attached 

 to the hyoid arch in bony fishes, while the inclusion of the 

 vomer of the dog (p. 395), under the head " Bones in rela- 

 tion to the Olfactory Capsules," fails to impress upon the 

 student the fact that this bone is morphologically an ossifi- 

 cation of the mucous membrane of the roof of the mouth. 

 That great credit is due to Mr. Reynolds for his con- 

 scientious industry and honesty of purpose there is 

 abundant internal evidence to show, but the product of 

 his labours is— a book which is just good enough to 

 suggest how valuable it might have been had its com- 

 pilation been entrusted to a qualified morphologist. At 

 the same time, Mr. Reynolds is to be congratulated on 

 NO. 1446, VOL. 56] 



the large amount of information which he has brought 

 together, and on the fact that he has not neglected the 

 extinct forms. And although, in its present form, the 

 book cannot with advantage be used as a book of re- 

 ference, while its abrupt and disconnected style renders 

 it ill-adapted for continuous reading, there can be litt 

 doubt that if, when a second edition is called for, the 

 plan of the book were simplified, the inaccuracies cor- 

 rected, and the various chapters and sections connected 

 up and coordinated, the book would prove a valuable 

 addition to the student's library. 



OUR BOOK SHELF. 

 Studien iiber Dampfspannkraftmessungen. By Georg 

 W. A. Kahlbaum ; with the co-operation of C. G. von 

 Wirkner and others. Part ii. ist half. Pp. x -f- 221. 

 (Basel : Benno Schwabe, 1897.) 

 In the first part of this work (Nature, March 8, 1894, 

 p. 436), measurements of the vapour pressures of a 

 number of substances were given. The method used in 

 the determinations was also fully described, and its 

 accuracy discussed. The author's intention was to de- 

 vote the second part of the book to a discussion of the 

 theoretical bearing of the experimental material collected. 

 Further experiments with substances belonging to 

 chemical groups other than those previously examined 

 revealed, however, the necessity of first enlarging this 

 experimental material ; the present volume contains the 

 results of these additional measurements. The experi- 

 mental method employed is the same as before, and the 

 results are given in the form of numerical tables and of 

 curves. Every precaution appears to have been taken 

 to secure accuracy. Where previous observations exist, 

 the results are compared together, and the satisfactory 

 agreement found between the results obtained by Ramsay 

 and Young, for example, by the statical, and by the 

 authors by the dynamical method, may be regarded as 

 further evidence of the trustworthiness of the latter. In 

 this volume the measurements extend from about o to 

 760 mm., except in cases where the solidification of the 

 substance prevented the measurements at lower pres- 

 sures. The substances for which new experimental re- 

 sults are given are benzene, brom-benzene, benzalde- 

 hyde, phenol, aniline, benzonitrile, benzyl alcohol, nitro- 

 benzene, benzoic acid, ethyl alcohol, propionic, normal 

 butyric, valeric, heptylic, isobutyric and isocaproic acids, 

 methyl-, dimethyl-, ethyl- and diethyl-aniline, phenyl- 

 methyl ketone, methyl benzoate and benzoyl chloride. 



In connection with the fatty acids, the accuracy of 

 Duhring's rule is discussed. The rule states that the 

 difference between the boiling-points of a liquid at some 

 standard pressure and at any other pressure divided by 

 the corresponding difference for some other liquid is a 

 constant quantity for that pair of liquids. This, it ap- 

 pears, is sufficiently accurate only when the liquids be- 

 long to a group of closely related substances, such as the 

 fatty acids. 



In conclusion, it is hardly necessary to point out the 

 great value, scientific and practical, of careful deter- 

 minations, such as those before us, of the vapour pressures 

 of liquids. 



The Induction Coil in Practical Work, including Rontgen 

 Rays. By Lewis Wright. Pp. vi + 172. (London : 

 Macmillan and Co., Ltd., 1897.) 

 The discovery of the Rontgen rays has created a revived 

 interest in many of the beautiful experiments that can be 

 performed with the aid of the Ruhmkorff induction coil, 

 and is thus indirectly a sufficient justification for the 

 appearance of this treatise of 172 pages. More especially 



