SCIENCE.— AD VERTISEMENTS. 



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. 



;-iuch crsytallized balls, 



Collections for Schools. 



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

 tained in a neat wooden box and accompanied by a /,6- 

 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 

 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. iSchool Bulletin]\\^i out. 



Loose Crystals. 



Small packages of free crystals for crystallographic study 

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

 proval bos.es of cabinet specimens by express or freight. 



ROY HOPPING, 



MINERAL DEALER, 



504=506 Liberty Building, 

 Liberty and Greenwich Sts. 



NEW YORK. 



NEW CATALOGUE. 



We have recently issued a new edition, revised and 

 enlarged to 64 pages, of our Catalogue of 



Books on Chemistry, Chemical 

 Technology in Physics. 



It is arranged by subjects, and includes all the 

 standard books in Chemical and Physical Science, as 

 well as the recent 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. 



in the country to-iiny offers so tiigh a class ot 

 Indian Stone Relics as I am now offering to 

 advanced collectors, having recently bought 

 several collections, giving every type of Ar- 

 row and Spear Heads from )4 inch to 7 inches. "Drills, Axes. 

 Celts, Pipes, Mortars, Pestles, Hematites, Banner Stones.Amu- 

 lets, also, European Stone Relics. Nothing surpasses and few 

 approach my stock of l.i.OOO pieces. Goods sent on selection 

 Catalogue for stamp Also Catalogue, No. 8, Minerals, Fos- 

 siLS, etc. I.. W. STILWELL. Deadwood. South Dak 



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 with water and sweet- 

 ened." 



Descriptive pamphlpt free on application to 

 Rumford Chemical Works, Providence, R. 1. 



Bewart of Substitutes and Imitations. 



For sale by all Druggists. 



The Universuzn Clock 



represents the Universe. It shows the earth revolving round 

 its axis, giving the time at the point passing the sun, the 

 stars in tlieir proper position, and their rising and setting. 



The Northern Hemisphere Clock 



Shows at a glance the time at every place between the North 

 Pole and Equator. 



UNIVERSUM CLOCK CO., 1 BEACON ST.. BOSTON, MASS. 



HOUGH'S "AMERICAN WOODS" 



A publication illustrated by actual specimens. Prepara 

 TioNS OF Woods for Stereopticon and Microscope, Speci- 

 mens OF Woods for Class Use, Etc. If you are interested 

 in woods or trees in any way, send for our circulars and 

 sample specimens. Address 



R. B. HOUGH, LOWVILLE, N. Y. 



NEARLY READY. 

 THE 



COMMERCIAL ORGANISATION 

 FACTORIES. 



Full of Diagrams and Practical PorNTS. 



Spon & Chamberlain, 12 Cortlandt St., N. Y. 



COLLECTIONS OP MINERALS. 



Scientifically selected, arranged and labeled. Uneqalled for beauty and practical value. 



MINERALS FOR LABORATORY "WORK. 



Sold by the pound at very low prices. 



CABINET SPECIMEIsrS in greatest variety. 



124-page Illustrated Catalogue, 2oc. in paper, 50c. in cloth, 

 •i-l-page Illustrated Price-Lists, 4c. ; Bulletins and Circulars Free. 



GEO. L. ENGLISH & CO., Mineralogists, 64 East I2tli St., New York. 



