SCIENCE.— AD VER TISEMENTS. 



Dec. 1, 18P6. Just Published. Sixth Edition of 



THE MICROSCOPE ^SSuTE^T^ilfDT- 



By SIMON HENRY GAQE, Professor of Microscopy, His- 

 tology and Embryology in Cornell University and the 

 New York State Veterinary College, Ithaca, N. Y., U.S A. 

 Sixth edition, rewritten, greatly enlarged, and illustrated 

 by 165 figures in the text. Price, $1 .50, postpaid. 



COMSTOCK PUBLISHING CO., Ithaca, N. Y. 



Wow Ready, 



Light, Visible and invisible. 



By SILVANUS P. THOMPSON, D.Se., 



F.R.S., MR. I., Principal of. atid Professor of Physics in, 



the City and Guild's Technical College, 



Finshury, London. 



With Numerous Illustrations. 

 12mo. Cloth, pp. xii+294. Price $1.50. 



CONTENTS OF THE VOLUME: 



Light and Shadows. 



The Visible Spectrum aud the Eye. 



Polarization of Light. 



The Invisible Spectrum (nltra-violet part). 



The Invisible Spectrum (iufra-ied part). 



Eontgen Light. 



This volume brings up to date the late discoveries and 

 theories, and it will be found invaluable both to the student 

 and to the general reader. The subject is treated in a sim- 

 ple, masterly, and, at the same time, popular way. 



THE MACMILLAN CO^PAn, SB Fifth Ave,, New York. 



NEW CATALOGUE. 



We have recently issued a new edition, revised and en- 

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D. Van Nostrand Company, 



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Beware of Substitutes and Imitations. 



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HOUGH'S "AMERICAN WOODS" 



A publication illustrated by actual specimens. 



WOODS FOR THE STEREOPTICON 



Enabling you to show upon the screen characteristic 

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WOODS FOR THE MICROSCOPE 



Sections 1-1200 in. thick showing three distinct views ofr 

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VIEWS OF TYPICAL TREES 



From Nature, photographs and stereopticon views. 



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COMPLETE LABORATORY EQUIPMENT OF OUR OWN MANUFACTURE. 

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Catalogue P Free to School ZIEGLER ELECTRIC CO., "Duty Free" Importations IroiB' 



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