il SCIENCE.— AD VERTISEMENTS. 
The ten numbers of SCIENCE begin- 
ning with the issue of August 13th, will 
contain full reports of the meetings of 
the American Association for the Ad- 
vancement of Science, at Detroit, and of 
the British Association, at Toronto. 
These ten numbers will be sent to any 
address for One Dollar. 
THE MACMILLAN COMPANY. 
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Descriptive pamphlet free. 
Rumford Chemical Works, Providence, R. I. 
Beware of Substitutes and Imitations. 
Dec. 1, 1896. Just Published. Sixth Edition of 
THE MICROSCOPE AND MICROSCOPI- 
CAL METHODS, 
By SIMON HENRY GAGE, 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. 
Cambrian Fossils. 
from the St. Croix (Potsdam) sandstone for sale. 
Trilobites. Send for low prices. 
W. A. FINKELNBURG, WINONA, MINN. 
NEW CATALOGUE. 
A large collection of Upper 
Mississippi Cambrian fossils 
Mostly 
We haye recently issued a new edition, revised and en- 
larged to 64 pages, of our catalogue of 
Books on Chemistry, Chemical 
Technology and Physics. 
It is arranged by subjects, and includes all the standard 
books in Chemical and Physical Science, as well as the re- 
cent literature up to date. 
A copy of this Catalogue will be sent free by mail to any 
address. 
D. Van Nostrand Company, 
Publishers and Importers of Scientific Books, 
23 Murray St. and 27 Warren St., New York. 
Eor 12 Cents 
I will mail a finely finished original photo, 
cabinet size, of Sioux Indian Chief, SITTING 
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on selection. Give reference. After seeing sample you will 
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15,000 Flint Stone Ancient Indian Relics. 100,000 Mineral 
and Fossil Specimens. Catalogue forstamp. 13th year. 
L. W. STILWELL, Deadwood, South Dak. 
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 of 
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WOOD SPECIMENS FOR CLASS USE 
Nothing equals these for use in the class-room. 
VIEWS OF TYPICAL TREES 
From Nature, photographs and stereopticon views. 
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If you are interested in wood or trees in any way send for 
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Address R. B. HOUGH, Lowwville, N. Y. 
