446 



SCIENCE 



[N. S. Vol. XXXIV. No. 875 



in the gold castings, and the armadillo pottery, 

 a similarity which consists essentially in the 

 use of detached figures, nodes and fillets, as 

 described before. He also calls attention to 

 the frequent occurrence of the head with up- 

 turned snout — the alligator-head design of 

 painted pottery — in this technique, a feature 

 that had escaped the attention of previous 

 students. At least one of them has, however, 

 the type of proboscis rolled down (PL 58, Fig. 

 g) which is so common on the plateaus of 

 Costa Rica. In this case also the rigidity of 

 the fundamental form seems particularly 

 suggestive to the writer, because a variety of 

 animals have all been presented in analogous 



Franz Boas 



outlines. 



Columbia University 



Principles of Chemical Geology. A review of 

 the Application of the Equilibrium Theory 

 to Geological Problems. By James Vin- 

 cent Elsden, D.Sc. (London), E.G.S. Lon- 

 don and New York, Whittaker and Co. 

 1911. 222 pages, with 44 figures. 

 While an imaginative geological writer has 

 recently asserted that " to be more productive 

 than it is, geology must become more specu- 

 lative," it is gratifying to note the steady ad- 

 vance that is being made in the explanation 

 of geological phenomena along the lines of es- 

 tablished principles in the fundamental sci- 

 ences of physics and chemistry. With the 

 rapid development of physical chemistry there 

 has been a corresponding improvement in con- 

 ceptions regarding processes that have taken 

 part in the production of the earth as we 

 know it. And every effort that is made to 

 place these fundamental concepts within the 

 reach of students of geology, and which suc- 

 ceeds as well as the book before us, should be 

 welcomed as a contribution of the first order 

 to the advancement of the science. 



But it must be borne in mind that any de- 

 veloping branch of human knowledge is an 

 assemblage of observations and conclusions of 

 variable degrees of accuracy and truthfulness, 

 subject to constant revision and readjust- 

 ment. And in the problem of the application 



of principles of physics and chemistry to the 

 phenomena of the earth, as a whole, and in 

 detail, these are the variable factors of di- 

 vergent opinion regarding the laws to be ap- 

 plied, and the still very inadequate data re- 

 lating to the phenomena to be explained, as 

 well as an accumulation of confl.ieting obser- 

 vations and of conclusions, in some instances 

 misleading or actually incorrect. Moreover 

 the multitudinous requirements in each branch 

 of learning prevent the worker generally from 

 acquiring independent ■ judgment in more 

 than one distinct branch of science. 



For these reasons each contribution to the 

 solution of the highly complex problems to be 

 found in the study of rocks and minerals 

 must have its particular characteristics aris- 

 ing from the point of view and range of ex- 

 perience of its author, as well as from the 

 source of his information and the quality of 

 his judgment. 



In the contribution made by Mr. Elsden 

 there appears to be the experience of a physi- 

 cist familiar with the subject of physical 

 chemistry, and capable of presenting the es- 

 sential principles in a clear and simple man- 

 ner, not wholly free, however, from the tech- 

 nology of the science. There is less of the 

 chemical side of the subject than the title of 

 the book suggests, which might better have 

 been " Principles of Physical Chemistry Ap- 

 plied to Geology," for there are phases of the 

 chemistry of the earth not touched upon. The 

 application of the principles discussed is well 

 made in most cases, and the examples that 

 may illustrate them are happily chosen from 

 the mass of recorded observations to be found 

 in the literature of geology and petrology. In 

 the selection and rejection of conflicting 

 opinions in certain instances the author's 

 judgment has been on the side of the more 

 probable — according to the opinion of the 

 reviewer. But the author does not appear to 

 possess personal knowledge of the petrograph- 

 ical and mineralogieal data appealed to in 

 illustration of particular principles. 



The author states that one of the main ob- 

 jects he has had in view is to show that the 



