SCIENCE.— AD YER TISEMENTS. 



RARE MINERALS. 



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

 carbonate of calcium, pure white, 2Sc. 



BKDEMITE, bright yellow on red wnlfenite, Arizona, SOc. 



Collections for Schools. 



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

 tained in a neat wooden box and accompanied by a 1,6- 

 page guide book (XIII., Guide for Science Teaching, Bos- 

 ton Society of Natural History). Price, complete, ll.OO. 



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 }\iil o\xt. 



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, 

 5 and 7 Dey Street, NEW YORK. 



A German "Poole's Index." 



Bibliographie der dentschen Zeitschriften Littera- 

 tur, volume I., $2.50, paper covers. An alphabetical 

 topical index to 275, mostly scientific, German peri- 

 odicals for the year 1896, exclusive of Medicine and 

 Technology. 



LEMCKE & BUECHNER, NEW YORK. 

 SIXTH EDITION. 



THE MICROSCOPE T^lTtK"'" 



By SIMON HENRY QAaE, 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. 



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." 



Desciiptive pamphlet free on application to 

 Rumford Chemical Works, Providence, R. I. 



Beware of Substitutes and Imitations. 



For sale by all Druggists. 



NEW CATALOGUE. 



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

 larged to 64 pages, of our catalogue of 



Books on Cliemistry, Chemical 

 Teclinology 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 



Physical Chemical Microsccpical ^ Electrical Ipparalus 



Established COMPLETE LABORATORY EQUIPMENT OF OUR OWN MANUFACTURE. 



1882. X-RAY APPARATUS AND CROOKE'S TUBES A SPECIALTY. 1894. 



Catalogue P Free to School ZIEGLER ELECTRIC C0>, " Duty Free " Importations from 



Officials and Science Teachers. 141 Franklin St.. BOSTON, MASS. Foreign Manufacturers. 



( CABINET SPECIMEWS. BEST AND MOST COM- 



] SYSTEMATIC COLLECTIONS. PLETE STOCK 



>- FOR LABORATORY USE. IN THE COUNTRY. 



124-page Illustrated Catalogue, giving crystallograpliic system, hardness, specific gravity, chemical com- 

 position and formula of every mineral. 25c. in paper ; 5Uc. in cloth. 



44=page Illustrated Price Lists, 4c. Circulars and Bulletins Free. 



MINERALS. 



GEO. L. ENGLISH & CO., Mineralogists, 64 E. 12th St., N. Y. 



