SCIENCE.— AD VER TISEIIENTS. 



RARE MINERALS. 



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



carbonate of calcium, pure white, 25c. 

 EKDEJVilTE, bright yellow on red wulfenite, Arizona, 50c. 

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



2Sc, 3Sc. 



Collections for Schools. 



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

 tained in a neat wooden box and accompanied by a It6- 

 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 iormula, 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 i\is,t ont. 



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 freigbt. 



ROY HOPPING, 



MINERAL DEALER, 

 5 and 7 Dey Street, NEW YORK. 



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 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, diemical 

 Teclmology 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. 



SIXTH EDITION. 



THE MICROSCOPE '^MiSs':'- 



By SIMON HENRY OAQE, 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. 



Fox- 3.S Cezitfil 



I will mail a finely finished original photo, 

 cabinet size, of Sioux Indian Chief, SITTIN<J 

 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 Belies. 100,000 Mineral 

 and Fossil Specimens. Catalogue for stamp, loth year. 

 L. 'W. STII.'WEIil., Deadwood, Sonth Dak 



Living Plants and Their Properties. 



By Professor J. C. ARTHUR, Purdue University, and Pro- 

 fessor D. T. MacOOUGAL, University of Minnesota, A 

 timely book of 12 independent chapters, viz; The special 

 senses of plants, development of irritability, universality of consciousness and pain, compass plants, sensitive plants, oppos- 

 ing factors of increase, influence of cold, significance of color, chlorophyll and growth, history of leaves, the right to live, 

 and comparisons between plants and animals. The subjects included are treated from new points of view with original 

 illustrations. The language is non-technical, and the book will be of interest to the general reader as well as to the biologist. 



Printed on enamelled paper with marginal sub-titles, 30 illustrations, 210 pp., 8vo, bound in cloth. Price, $1.25 ppd. 

 BAKER &, TAYLOR. MORRIS & WILSON, 



5 AND 7 East 16th St.. New York. MrNNEAPOLis, Minn. 



Rare Minerals. 



THAUaiASITE from West Paterson, N. J., a unique compound of the 

 sulphate, silicate and carbonate of calcium with. 42 per cent, of water. 

 An excellent, attractive, cabinet size specimen, postpaid for 14 cents, 



CRYSTALLIZED ARSENIC from Japan, in balls % to ?^4-incli diameter, postpaid, 16 cents. CONTACT TWINS OF 



QUARTZ, postpaid, Jfl.OO. TWISTED STIBN^TE crystals and groups, 2S cents, postpaid. MOUNTAIN LEATHER, a. 



great novelty, postpaid, lie, 16c., 22c. and 27c. 134-page Catalogue, describing every mineral, 25c. in paper; 50c. in clothe 



44-page Price-List, 4c. Bulletins and Circulars Free. 



GEO. la. ENGLISH & CO., Mineralogists, 64 E. 12tli St.. New York. 



