il SCIENCE.—AD VER TISEMENTS. 
A NOTABLE BOOK. 
A Monograph, 
Structural and Systematic of 
the Order Oligochaeta. 
By 
FRANK EVERS BEDDARD, M.A., F.B.8. 
Demy 4to, with Plates and Illustrations. 
Price, $12.50. 
Times :—‘‘A most elaborate and exhaustive treatise, 
sumptuously printed and illustrated, on the anatomy, 
classification, and biological relations of an important 
order of segmented worms found in fresh water.’’ 
For Sale by all Booksellers. Send for Catalogue. 
Orford University Press, 
AMERICAN BRANCH: 
91 and 93 Fifth Ave., NEW YORK. 
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Beware of Substitutes and Imitations. 
For sale by all Druggists. 
RARE MINERALS. 
THAUMASITE, from Paterson, N. J., a sulphate, silicate and 
carbonate of calcium, pure white, 25c. 
EKDEMITE, bright yellow on red wulfenite, Arizona, 50c. 
NATIVE ARSENIC, Japan, 44 to 34-inch ersytallized balls 
25c, 35c. 
Collections for Schools. 
ALPHA COLLECTION, twenty-five specimens in trays, con- 
tained in a neat wooden box and accompanied by a 46- 
page guide book (XIII., Guide tor Science Teaching, Bos- 
ton Society of Natural History), Price, complete, $1.00. 
CABINET COLLECTIONS, 100 specimens, small size, $5.00. 
100 specimens, large size, $10.00. These specimens are 
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EXCELSIOR COLLECTION for high schools and colleges 
200 specimens, nicely mounted on wooden blocks, with 
beveled fronts for receiving labels. Price, packed 
$100.00. School Bulletin just out. 
Loose Crystals. 
Small packages of free crystals for crystallographic study 
may be sent for inspection by mail at small cost. Ap- 
proyal boxes of cabinet specimens by express or freight. 
ROY HOPPING, 
MINERAL DEALER, 
504-506 Liberty Building 
Liberty and Greenwich Sts. i NEW YORK. 
SPECIAL NOTICE. 
Position desired in Engineering Offices, with 
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"HOUGH’S “AMERICAN WOODS” 
A publication illustrated by aciwal specimens. 
WOODS FOR THE STEREOPTICON 
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Sections 1-1200 in. thick showing three distinct views of 
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From Nature, photographs and stereopticon views. 
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Perfectly adapted to printing (with type or steel plate), 
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If youare interested in wood or trees in any way send for 
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Address R. B. HOUGH, Lowville, N. Y. 
