Geology. 557 



subdivision of physics a list of well-selected reference books is 

 given. Also brief comments on the characteristics of these books 

 are made. Finally, the problems at the end of each complete 

 chapter have been classified with heavy type, marginal titles and 

 numerical answers are appended. On the whole, the book has 

 been greatly improved by the process of revision so that it is 

 now a thoroughly reliable text. h. s. u. 



14. General Physics : Mechanics and Heat / by J. A. Culler. 

 Pp. ix, 311, with 225 figures. Philadelphia, 1909 (J. B. Lip- 

 pincott Co.). — This book is designed for the use of college stu- 

 dents who possess a working knowledge of plane trigonometry. 

 Proofs of various formulae which involve the integral calculus 

 are given in the appendix. This portion of the book also con- 

 tains tables of physical constants, of natural trigonometric func- 

 tions, and of common logarithms. In the prefatory note, the 

 author says : " The aim of the writer has constantly been to say 

 the words that would help the student to understand the subject." 

 In this endeavor as well as in the matter of accuracy of state- 

 ment he has often failed. Two typical quotations will suffice to 

 justify this adverse criticism. 



On page 69 the following statements are made. " The centre 

 of gravity and centre of mass coincide, but their definitions are 

 different." " The centre of mass is a point whose distance from 

 the three planes of reference is equal to the mean distance of the 

 particles, supposed equal, from the same planes." 



On page 39 Newton's laws of motion are stated in the follow- 

 ing new and incorrect forms. 



" (1) Every body of matter persists in its state of rest or 

 motion. 



" (2) The effect of an impulse in changing the momentum of a 

 mass of matter is independent of other impulses which may be 

 applied at the same time and of the momentum which the mass 

 may already have. 



" (3) The application of a force is always accompanied by an 

 equal resistance in the opposite direction, and the energy 

 expended by any body acting as agent is equal to the energy 

 received by another body which resists the agent." h. s. u. 



II. Geology. 



1. Publications of the United States Geological Survey, 

 George Otis Smith, Director. — Recent publications of the U. S. 

 Geological Survey are noted in the following list (continued 

 from p. 80) : 



Topographic Atlas. — Thirty-eight sheets. 



Folios — No. 166. El Paso Folio, Texas. Description of the 

 El Paso District ; by G. B. Richardson. Pp. 11 ; 2 maps, 15 

 figures. 



No. 168. Jamestown-Tower Folio, North Dakota. James- 

 town, Eckelson, and Tower Quadrangles. Description of James- 



Am. Jour. Sci. — Fourth Series, Vol. XXVIII, No. 168.— December, 1909. 

 37 



