SCIENCE-ADVERTISEMENTS 



JACKSON AND BLACK'S 



Elementary Electricity 

 and Magnetism 



has been revised, enlarged, and brought up 

 to date by N. Henrt Black, of the Roxbury 

 Latin School, Boston, one of the authors of 

 Black and Davis' PRACTICAL PHYSICS. 



A new edition of this standard work is 

 sure to interest all teachers of physics. 



Though 



Especially suited for use as a class text 

 in special courses in electricitjr for those 

 who have had one year of physics, it is.i^ 



Nevertheless 



Useful for reference work and topical 

 reading by students in regular courses in 

 physics. 



And 



Is an excellent summary of the whole 

 field of electricity for electrical workers 

 and the general reading public. 



THE MACMILLAN COMPANY 



64-66 Fifth Ave., New York 

 Chicaffo Boston Dallas Atlanta San Francisco 



Queen's University- 

 Kingston, Canada, April, 1919 



Applications will be received by the undersigned up to 

 Jul; 1st, 1919, for the following positions: 



1. Professor of Latin, Salary S3,000, rising to $3,500. 



2. Professor of English Literature, Salary $3,000, rising 



to $3,500. 



3. Professor of Modem History, Salary $3,000, rising 



to $3,500. 



4. Professor of Physiology, Salary $3,000, rising to 



$3,500. 



5. Research Professor in either Chemistry or Physics, 



Salary $2,500 to $3,500, according to training and 

 experience. 



6. Professor of Chemistry, Salary $3,500. 

 7 Lecturer in Physics, Salary $1,500. 



R. BRUCE TAYLOR, Principal 



PETRI DISHES 



"We have a small stock of first quality petri dishes 98x 10 mm. 

 These are packed, 1 gross dishes and covers in a case. Since 

 this is a discontinued size, we offer these dishes, while they last, 

 at §15.00 per gross, boxes included, f. o. b. factory. 



H. C. FRY GLASS CO. 



ROCHESTER, PA. 



The IViiorosoope 



12th Edition, Published April 10, 1917 



Re-Wrltten and largely Ra-IIIuatratad 



Bf SIMON HENRY CAGE of Cornell Uniraralty 



Postpaid $3.00 



COMSTOCK PUBLISHING CO., Ithaca, N. Y. 



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LENZ APPARATUS CO. 



Manufactu rers — Dealers — I m po rte ra 



18 East Sixteenth Street 

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OPTIC PROJECTION 



Principles, installation and use of the Mag'o Lantern, Opaque 

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 THE COMSTOCK PUBLISHING CO.,Ithaca.N Y. 



WANTED 



Audubon's Birds of America 



7 Volumes Octavo Edition 



Please state condition of binding and if all the plates 

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FREDERICK C. HARRIS 



Box 2244 BOSTON, MASS. 



Memoirs of the Wistar Institute of Anatomy and 

 Biology. No. 6, 1915 



THE RAT 



Data and Reference Tables. 278 Pages. 89 Tables. 



Bibliography. 

 Compiled and Edited by HENRY H. DONALDSON. 



Postpaid, $3.00. 



The Wistar Institute 



Philadelphia, Pa. 



WHITE MICE FOR SALE 



Laboratory Stock, $30 a hundred, P. O.B. Qarrlson.N.y. 

 Guinea Pig*, Rats, and other Laboratory Animals 



Sta/nding orders solicited 



The Laboratory Animal Supply Co. 

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