792 



SCIENCE 



[N. S. Vol. XXIX. No. 750 



the influence of forests on climate, and on 

 changes of climate, to see what the greatest 

 authority on climatology has to say on these 

 subjects. Eegarding the former, Hann says 

 that the influence of forests upon rainfall is 

 a slight one. Eegarding the latter, while 

 granting that Stein, Huntington and others 

 have shown that there is a general desiccation 

 going on in Asia, the author adds : " How far 

 in all these accounts we have to do with a 

 progressive desiccation, and how far with cli- 

 matic oscillations, is still a question." In 

 other words, there is as yet no sufficient evi- 

 dence for believing in considerable permanent 

 changes. Oscillations, yes, some of longer, 

 others of shorter periods; but permanent pro- 

 gressive changes, no, not yet. 



The teacher of climatology will feel safe 

 and sure with Hann's book on his study shelf, 

 close at hand. The man of science, in what- 

 ever field he may be working, who needs the 

 fullest, latest, most authoritative information 

 on climatology, will find in Hann's new vol- 

 ume what he seeks, and he wiU find it clearly 

 set forth. 



The remaining volumes, dealing with the 

 special climates of the different parts of the 

 world, will be published shortly. 



E. DeC. Waed 



Reservoirs for Irrigation, Water Power and 

 Domestic Water Supply. By James Dix 

 Schuyler, M.Am.Soc.O.E., M.Inst.C.E., etc. 

 Second edition revised and enlarged. Bound 

 in cloth ; dimensions, 6 J by 10 J inches. Pp. 

 573; illustrations 381; folding plates 6. 

 Price, $6.00. New York, John Wiley and 

 Sons; London, Chapman and Hall, Ltd. 

 The growing importance of storage reser- 

 voirs and their appurtenant structures in the 

 development of domestic water supplies, hy- 

 draulic power plants and irrigation projects 

 warrants the revision and enlargement of this 

 already useful work. The scarcity of water 

 furnished by the normal flow of streams for 

 irrigation in the arid regions; the increasing 

 demand for water power due to the decreasing 

 coal supply and the increasing possibilities of 

 electric power and the sanitary needs of the 

 many growing towns and cities throughout the 



entire country are requiring wide information 

 on the subject of water storage and water- 

 storage structures. This information abounds 

 in the book under review, as may be inferred 

 from its chapter subjects, the titles of which 

 are as follows: Eock-fiU Dams; Hydraulic-fill 

 Dams; Masonry Dams; Earthen Dams; Steel 

 Dams; Eeinforced Concrete Dams, and Mis- 

 cellaneous. In these chapters are discussed 

 individually more than 200 important dams, 

 of which the majority are of the masonry 

 type. However, over a score each of rock-fill, 

 hydraulic-fill and earthen dams and nearly a 

 half score of steel and reinforced concrete 

 dams are described in detail. 



The style and arrangement of subject matter 

 of the book lack uniformity and its substance 

 is rather a collection of facts relating to dams 

 and reservoirs than a scientific treatise thereof. 

 The author has included but little of the 

 principles of design and construction except 

 as incident to description. The work is there- 

 fore better adapted to use for reference than 

 for study. It is an excellent memory store- 

 house for the practising engineer. Such 

 works, although not forming the highest type 

 of engineering literature, are none the less 

 essential parts thereof, and are especially val- 

 uable as sources from which to draw infer- 

 ences from basic facts. 



The first edition of this work found its way 

 into the libraries of many engineers and the 

 second edition is certain to find a still greater 

 circulation. Sufficient new and rewritten 

 material has been incorporated into the text 

 to make the book essentially a new work. In 

 addition to the new and revised subject matter 

 the book contains 234 new cuts and photo- 

 graphs and 3 plates. The work will, there- 

 fore, be equally of interest to those familiar 

 and unfamiliar with the first edition. 



F. W. Hanna 



U. S. Reclamation Sebvice 



SCIENTIFIC JOURNALS AND ARTICLES 

 The American Naturalist for April opens 

 with a paper on "Heredity of Hair Color in 

 Man," by Gertrude C. and Charles C. Daven- 

 port. This article includes a number of tables 

 showing the distribution of color in the off- 



