SCIENCE— ADVERTISEMENTS 



Marine Biological Laboratory 



WOODS HOLE, MASS. 



Biological Material 



1 . Zoolos7> Preserved material of all types of animals for 

 class work and for the museum. 



2._ Embryolosy- Stages of some invertebrates, fishes (in- 

 cluding Acanthias, Amia and Lepidosteus), Amphibia, and 

 some mammals. 



3. Botany. Preserved material of Algae, Fungi, Liver- 

 worts, Mosses, Ferns and Seed Plants, 



4. Microscope slides in Bacteriology, Botany and Zoology. 



5. Life Histories, Germination Studies, and Natural Hi a- 

 tory Groups. Catalogues furnished on application to 



GEORGE M. GRAY, Curator 

 Woods Hole, Mass. 



NOW READY 



The Physics of the Air 



By WILLIAM J. HUMPHREYS, Ph.D. 



Professor of Meteorological Physics, United States 



Weather Bureau 



A rational and deductive treatise on the physics of 



the atmosphere. Oi great value to meteorologists, 



physicists and the aviator. 



678 Pages, Illustrated, Index, Svo. Price, ^5 

 Address orders and inquiries to 



THE FRANKLIN INSTITUTE 



PHILADELPHIA, U. S. A. 



ORGAN OF CORTI 



Have you slides of this structure? 



We can supply you with prepara- 

 tions that show every detail. These 

 slides are of a grade that is usually 

 found only in research collections. 



Single Slides $1.25 



Ten or more, each $1.00 



Every slide is guaranteed 



Delivery hnmediate; we have delayed 

 listing this preparation, until we ac- 

 tually had it on our stock shelves. 



General Biological Supply House 



1 177 East 55th Street CHICAGO, ILL. 



Western RepruentatloaoJ the Supply Deparlmeni of Marine 

 Biological Laboratory;, Woods Hole, Mats. 



POSITION OPEN FOR TEACHING FELLOW IN 



PHARMACOLOGY, AT WESTERN RESERVE 



MEDICAL SCHOOL, CLEVELAND 



Intended as a short-term (one- or two-year) ap- 

 pointment, primarily for the training of the ap- 

 pointee. Salar3% $150 per month. Applications 

 should state scientific training and experience. 

 Address Dr. T. Sollmann, 1353 East Ninth Street, 

 Cleveland. 



TH© IVIIorosoope 



12th Edition, Published April 10, 1917 



Ro-Written and largely Rs-IIIustrated 



By SIMON HENRY GAGE of Cornell Unimralty 



Pootpaid $3.00 



COMSTOCK PUBLISHING CO., Ithaca, N. Y. 



MERCURY 



C. p. and redistilled in any 

 quantity 



THE CHEMICAL PRODUCTS CO. 



2715 St. Clair Ave., N. E. 

 CLEVELAND, OHIO 



