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766 Broadway, New York. 

 Importer of Scientific Books and Periodicals. 

 Branches : Leipzig, Hospital Str. 16 ; London, 26 

 King William Str., Strand. 



ft WESTERMANN & CO., 



(Established 1848.) 



838 Broadway . . . NEW YORK, 



FOREIGN BOOKSELLERS AND IMPORTERS. 



MAGAZINES AND REVIEWS!! 



Complete sets of all the leading Magazines and Reviews and 

 back numbers of several thousand periodicals, for sale at low 

 rates. Full files of Science, either bound or unbound, or odd 

 volumes and numbers supplied. Subscriptions taken on favorable 

 terms for any periodical either American or foreign. Address 

 THE AMERICAN AND FOREIGN MAGAZINE DEPOT, 

 47 Dey street, New York City. 



SCIENTIFIC LIBRARY FOR SALE. 



One of the largest and most complete libraries in the west, in 

 the departments of Geology and Palaeontology, embracing over 

 1250 catalogued numbers, and numerous maps and pamphlets, is 

 for sale. Address A. H. WORTHEN, Springfied, Ills. 



"THE ELECTRICAL REVIEW," 



An illustrated weeklyjournal.is theacknowledgcd lead- 

 er in the world of electrical science. Edited with care, 

 its editorial opinion is reliable, its news columns bright 

 and instructive. $3.00 per year; single copies, 10 cents. 



23 PARK BOW, NEW YORK. 

 tW Best advertising medium in the electrical field. 



I 



James W. Queen & Co, 



Manufacturing Opticians, 



921 CHESTNUT ST., PHILADELPHIA, 



OPTICAL AND SCIENTIFIC INSTRU- 

 MENTS OF ALL KINDS. 



PUBLISHERS OF THE 



MICROSCOPICAL 

 BULLETIN. 



(Sample free ) 



We Publish our Catalogues in Parts, as follows, and will mail 



upon application such as may be desired by those interested. 

 Part i. Mathematical Instruments, Drawing Paper, etc. 162 pp. 

 Part 2. Optical Instruments, including Spectacles, Microscopes, etc. 

 188 pp. 



Part 2a (supplement). Astronomical Telescopes and Accessories. 35 pp. 

 Part ib (supplement. Opera, Field and Spy Glasses. 32 pp. 

 Part ic (supplement). Second-hand and other Microscopes, Objectives, 

 etc. 16 pp. 



Part 3. Projecting Lanterns and Slides. 150 pp. 

 Part 4. Physical Instruments. 250 pp. 



Part 4# (supplement). Chemical Apparatus, Balances, etc. 50 pp. 

 Part 4^ (supplement). Second-hand Physical and Chemical Apparatus. 

 16 pp. 



Part 4c (supplement). Chemicals. 48 pp. 



Part 5. Meteorological Instruments, Hydrometers, etc. 120 pp. 

 Part 6. Photographic Cameras, Lenses and Materials. 48 pp. 



AID WILL BE GIVEN by 



the officers of the American Humane 

 Association towards passing, perfect- 

 ing, and enforcing laws for the pro- 

 tection of birds. Address G. E. 

 Gordon, president. Thomas E. 

 Hill, secretary. Office, 103 State 

 street, Chicago. 



INFORMATION WANTED, 



upon the needless destruction of 

 birds, with facts and figures, by the 

 Committee on Protection of Birds, 

 of the Am. Ornithologists' Union. 

 Address Care of Am. Mus. Nat. 

 Hist., New York City. 



NOTICE TO SUBSCRIBERS. 



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