SCIENCE.— AD VER TISEMENTS. 



New Catalogues. 



I issue new catalogues of Scientific Apparatus 

 every month or so and am always glad to send them 

 to college professors and other interested scientists. 



Price-Lists now in Press or in Preparation. 

 Number 195. 



Rowland D'Arsonval Galvanometers ; Wall and 

 Table Patterns. 



Number 200. 



"W-S" X-Eay Plants; comprising seven outfits, 

 with illustrated descriptive matter. 



Number 205. 



Cable Testing Apparatus, Meter Bridges, Con- 

 ductivity Apparatus, etc. 



Number 210. 



Willyoung Adjustable Condensers, and Standard 

 Mica Condensers. 



Number 215. 



Elementary Laboratory Apparatus, chiefly Elec- 

 trical. 

 Number 220. 



Willyoung Induction Coils, with " Ideal " Auto- 

 matic Vibrator. 



James Q. Biddle, 



Dealer, Manufacturers' Agent and Importer, 



909 Drexel Building, Philadelphia. 



RARE MINERALS. 



THAUMASITE, from Paterson, N. J., a sulphate, silicate and 

 carbonate of calcium, pure white, 25c. 



EKDEMITE, bright yellow on red wulfenite, Arizona, SOc. 

 NATIVE ARSENIC, Japan, % to %-inch crsytallized balls, 

 2Sc, 3Sc. 



Collections for Schools. 



ALPHA COLLECTION, twenty-flve specimens in trays, con- 

 tained in a neat wooden box and aacompanied by a i6- 

 page guide book (XIII., Guide for 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 

 each accompanied by a label giving name, system of 

 crystallization, chemical formula, and locality, and make 

 a good working collection for a student. 



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 }\isiX)\sX. 



Loose Crystals. 



Small packages of free crystals for crystallographic study 

 may be sent for inspection by mail at small cost. Ap- 

 proval boxes of cabinet specimens by express or freight. 



ROY HOPPING, 



MINERAL DEALER, 

 504-506 Liberty Building, NEW YORK 



Liberty and Greenwich Sts. 



Horsford's Acid Phosphate 



Is the most effective and agreeable 

 remedy in existence for preventing in- 

 digestion, and relieving those diseases 

 arising from a disordered stomach. 



D. W. W. Gardner, Springfield, Mass., 

 says: " I value it as an excellent preventive of 

 indigestion, and a pleasant acidulated drink 

 when properly diluted v/ith water and sweet- 

 ened." 



Descriptive pamphlet free on application to 

 Rumford Chemical Works, Providence, R. I. 



Beware of Substitutes and Imitations. 



For sale by all Druggists. 



I will mail a finely finished original photo, 

 cabinet size, of Sioux Indian Chief, SITTING 

 BULL, with his Signature. Have 200 sub- 

 jects, all different, of leading Western Indians. 

 First-class work. Cabinet Size for 10 cents each. Some sent 

 on selection. Give reference. After seeing sample you will 

 want others. Indian Costume, Ornaments and Weapons. 

 15,000 Flint Stone Ancient Indian Relics. 100,000 Mineral 

 and Fossil Specimens. Catalogue for stamp. 13th year. 

 L. 'W. STIIi'WELI.. Deadwood, Soutli Dak. 



HOUGH'S "AMERICAN WOODS" 



A publication illustrated by actual specimens. 



WOODS FOR THE STEREOPTICON 



Enabling you to show upon the screen characteristic 

 structures projected from nature itself. 



WOODS FOR THE MICROSCOPE 



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

 grain under each cover glass. 



WOOD SPECIMENS FOR CLASS USE 



Nothing equals these for use in the class-room. 



VIEWS OF TYPICAL TREES 



From Nature, photographs and stereopticon views. 



WOODEN CROSS-SECTION CARDS 



Perfectly adapted to printing (with type or steel plate), 

 painting, India ink work, etc. 



If you are interested in wood or trees in any way send for 

 our circulars and sample specimens. 



Address R. B. HOUGH, Lowville, N. Y. 



