November iS, 1922] 



NA TURE 



661 



apparently the two outer planets were not much further 

 advanced in development than Jupiter and Saturn, 

 although their much smaller size would imply a shorter 

 career and more rapid development ; it therefore seems 

 probable that the order of formation of the giant planets 

 has been from the inside outwards, and not the reverse. 

 In the matter of the origin of the moon the author 

 does not favour the idea of its separation from the 

 earth by fission, holding that it grew from meteors 

 captured in the outer portion of the extended nebulosity 

 which represented the future earth. Throughout the 

 book he postulates the action of resisting medium ; 

 many systems of cosmogony do the same. 



A few errata may be noted. On p. 207 the author 

 pours scorn on the suggestion that the comets of Tuttle 

 and De Vico have any connexion with the planets 

 Saturn and Neptune respectively ; he overlooks the 

 fact that while the inclinations of their orbits are 55° 

 and 85 respectively, the inclinations of their major 

 axes are much less, so that in each case a shift of the 

 node by a few degrees would bring about intersection 

 with the planetary orbit. In the tables of planetary- 

 elements he adopts for Venus the very doubtful rotation 

 period of 68 hours, while he treats both the rotation 

 time and the position of the axis of Uranus as unknown, 

 whereas both are known within narrow limits. 



It is of course unreasonable to expect a book on such 

 a subject to settle definitely all the matters on which it 

 treats. Viewing it as a setting forth of the problems 

 presented by our system, with more or less plausible 

 solutions, it makes interesting reading. 



A. C. D. Crommelin. 



Reservoir and Other Dams. 



The Design and Construction of Dams : including 

 Masonry, Earth, Rock-fill, Timber, and Steel Struc- 

 tures, also the Principal Types of Movable Dams. 

 By E. Wegmann. Seventh edition, revised and 

 enlarged. Pp. xvii + 555 + plates A-Z + plates AA- 

 VV + plates i-in. (New York : J. Wiley and 

 Sons, Inc. ; London : Chapman and Hall, Ltd., 

 1922.) 505. net. 



MR. WEGMANN'S treatise has been before the 

 public for so long that we imagine its general 

 features will be more or less familiar to all who are 

 engaged in the domain of waterworks engineering. 

 The modest volume of 106 pages which appeared 

 thirty-four years ago has, however, developed con- 

 siderably in the course of time. It is now a ponderous 

 tome of some 600 quarto pages of text, with well over 

 100 full-page plates in addition. A volume of such 

 weighty proportions cannot fail to impress the reader 

 NO. 2768, VOL. I io] 



in point of size alone, and it undoubtedly represents a 

 considerable amount of patient toil in its compilation. 

 It is, in fact, not merely a text-book ; it is a work of 

 reference, containing diagrams and particulars of most 

 of the notable dams which have been constructed in 

 recent years. It is permissible to the critic to question 

 the wisdom of combining the two objects in a single 

 volume. To the student, a text-book of modest pro- 

 portions is a desideratum ; he needs something easy 

 to handle and conveniently portable, in the pocket if 

 need be. The work of reference, on the other hand, 

 is only required on occasion and may rest in the book- 

 case for long intervals. This combination of text- 

 book with an exhaustive, or nearly exhaustive, record 

 of existing examples is open to the objection that it 

 meets the convenience neither of the student nor of 

 the expert. However, we do not wish unduly to press 

 the point. 



In the seventh edition Mr. Wegmann has made his 

 treatise replete with information of a highly valuable 

 character. He has included a full description of the 

 Kensico dam, New York ; particulars of the movable 

 dams of the New York State Barge Canal ; and a brief 

 notice of the Camarasa dam in Spain. This last is 

 stated to be the highest gravity dam in the world, but 

 surely the Arrowrock dam is higher by 20 ft. Probably 

 what is meant is that the depth of water against the 

 Camarasa dam is not equalled elsewhere. Why is the 

 Arrowrock dam not included in the table of high 

 masonry dams ? Another very high dam omitted is 

 the Hetch-Hetchy dam. There is, perhaps, some 

 excuse for this omission, as the dam is yet under con- 

 struction. Still, its dimensions are known and it is 

 an important undertaking. A new chapter on crest 

 gates and siphon spillways has been added, with par- 

 ticulars of examples built both in America and else- 

 where, some of them of considerable size. 



The subject of dams, of course, is wider than the 

 sphere of waterworks engineering, although this is, 

 perhaps, the most important field of its application. 

 Mr. Wegmann's treatise covers dams as adapted to 

 river engineering operations, and cofferdams as used 

 in foundation work. Briefly, the volume consists of 

 four parts, the first of which deals with the design and 

 construction of masonry dams ; the second, with 

 earthen, rock-fill, timber, and steel dams ; the third 

 with movable dams, cofferdams, and overflow weirs ■ 

 and the fourth with recent dams of all classes. There 

 is an appendix containing the specifications for the 

 New Croton dam with various supplementarv notes 

 a lengthy bibliography which, unfortunately, is not 

 alphabetically arranged (the writer traced some works 

 with difficulty, and failed to find mention of Mr. Powell 

 Davis's book on irrigation works, which contains a 



