SCIENCE-ADVERTISEMENTS 



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."— -/ourna/ of Geography, Vol. XIII, 

 Jan. 1915. 



8vo, 1150 pages, 264 illustrations. Price, $7. SO 



Deacriptive CircuSarSent upon Request 



k. G. SEILER & CO. 



NEW YORK CITY 



TYPES AND BREEDS OF 

 FARM ANIMALS 



CHARLES S. PLUMB 

 $2.00 



An up to-date discussion of the several 

 types and breeds of horses, cattle, sheep, 

 goat, asses, mules and swine. It describes 

 the commonly accepted types, discusses the 

 original habitat, breed developments, 

 European and American breed history, the 

 work of pioneer breeders, famous animals 

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 important breeds have received more de- 

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The illustrations, numerous and excel- 

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Qinn and Company 



Boston New York Chicago London 



The Ellen Richards Research Prize 



The Naples Table Association for Promoting 

 Laboratory Research by Women announces the offer 

 of a research prize of $1000.00 for the best thesis 

 written by an American woman embodying new ob- 

 servations and new conclusions based on independent 

 laboratory research in Biology (including Psj'- 

 ohology), Chemistry or Physics. Papers published 

 before 1916 will not be considered and theses pre- 

 sented for a Ph.D. degree are not eligible. Theses 

 offered in competition must be in the hands of the 

 Chairman of the Committee on the Prize before 

 February 25, 1918. Application blanks may be ob- 

 tained from the secretary, Mrs. Ada Wing Mead, 

 823 Wayland Avenue, Providence, R. I. 



SCIENCE 



A [WEEKLY JOURNAL DEVOTED TO THE 

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LANCASTER, PA. GARRISON, N. Y. 



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OPTIC PROJECTION \ JULIEN'S POWER LATHES 



Principles, installation and use of tlie Mag'C Lantern, Opaque 

 Lantern. Projection Microscope and Moving Pictiu-e Machine: 

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 THE C OM STOCK PUBL ISHING CO., Ithaca, N Y. 



Queen's University- 

 Kingston Ontario, Canada 



Applications will be received until August 1st, for the positions 

 of Assistant Professor of Physics and also of Lecturer in Physics, 

 duties to commence September 26th, 1917. 



GEO. T. CHOWN, Registrar 



COMPACT— ACCURATE— DURABLE 



Use of Geologists, Mineralogists, etc., in SLICING 



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in preparation of MICROSCOPIC THIN SECTIONS. 



GUSTAVUS D. JULIEN 



3 Webtter Terrace NEW ROCHELLE, N. Y. 



The JMicrosoope 



I2th Edition, Published April 10, 1917 



Re-Written and largely Re-Illustrated 



By SIMON HENRY GAGE of Cornell University 



Postpaid $3.00 



COMSTOCK PUBLISHING CO., Ithaca, N. Y. 



