SCIENCE-ADVERTISEMENTS 



THE 

 PRINCIPLES OF 

 STRATIGRAPHY 



BY 

 AMADEUS W. GRABAU, S.M.. S.D. 



PROFESSOR OF PALEONTOLOGY IN 

 COLUMBIA UNIVERSITY 



"Should be on the reference shelf of every col- 

 lege, normal school, and large high school in the 

 United States." — Journal of Geography, Vol. XIII, 

 Jan. 1915. 



800, IISO pages, 264 illustTalioni. Prict, $7.50 



Dascriptive Circular Sent upon Request 



A. G. SEILER & CO. 



NEW YORK CITY 



Problems in the Calculus 



By DAVID D. LEIB 



Yale University 



The primary aim of this book is to pro- 

 vide a graded collection of problems in the 

 field of calculus. It is sufficiently varied 

 to be used as a supplement to any courg?. 

 Many of the problems are of a kind not 

 found in the ordinary textbook. A brief 

 description precedes each list of problems 

 in which new laws and formulas are em- 

 ployed. This is also a helpful discussion 

 of the technique involved and the common 

 errors to be avoided. 



No other such comprehensive book is 

 now available to American students. 

 224 pages. $1.00 



Ginn and Company 



Boston New York Chicago London 



Just Issued 



HHRYHRD HFRienN STUDIES 



The first volume of a scientific series for the anthropological and archaeological study of 



African peoples. 



©. BaTES, M.H., F.R.e.S., Editor 



P. H. STERNS, Ph.D., Assistant Editor 



This volume contains papers on Egyptian surgery in the Old Empire, Benin bronzes, 

 Swahih didactic hterature, burial customs of the Baganda, the paleolithic period in the 

 Nile Valley, ancient Egyptian fishing, the Nungu of Nigeria, etc., with a bibliography of 

 Africana for 1915. 



xiv + 292 pp., 30 heliofype ph., 30 photolith pis., many text figs., attractively 

 bound in cloth, $10.00, carriage free. 



Copies may be obtained from the Assistant Editor, H. A. S., Dept. D. 



aFRieaN OEPHRTMENT OF THE PEHBODY MCSEUM 



Harvard University ©ambridge, Mass. 



