SCIENCE.— AD VERTISEMENTS. 



RARE MINERALS. 



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

 carbonate of calcium, pure white, 2Sc. 



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



NATIVE ARSENIC, Japan, % to J^-iuch ersytallized balls, 

 2Sc, 3SC. 



Collections for Schools. 



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

 tained in a neat wooden bos and accompanied by a hS- 

 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 BuUeim jnst out. 



Loose Crystals. 



Small packages of free crystals for crystallographic study 

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

 proval boxes of cabinet specimens by express or freight. 



ROY HOPPING, 



MINERAL DEALER, 



NEW YORK. 



504-506 Liberty Building, 



Liberty and Qreenwich Sts. 



Cambrian Fossils. 



A large collection of Upper 

 Mississippi Cambrian fossils 



from the St. Croix (Potsdam) sandstone for sale. Mostly 



Trilobites. Send for low prices. 



W. A. FINKELNBURG, WINONA, MiNN. 



Dec. 1,1896. Just Published. Sixth Edition of 



THE MICROSCOPE ^S^LTE^x^ilfDT- 



By SIMON HENRY OAQE, Proiessor 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. 



The Thomas A. Scott Fellowship in Hygiene, 

 University of Pennsylvania. 



The Scott Fellowship in Hygiene at the University of Penn- 

 sylvania falls vacant October 1st, 1897. Individuals desirous 

 of applying for appointment to the position can obtain de- 

 tails of the governing regulations by communicating with 

 Prof. A. C. Abbott, Director of the Laboratory of Hygiene, 

 University of Pennsylvania, Philadelphia. 



Harvard University. 



Lawrence Scientific School 



OFFERS COURSES IN 



Civil EnglneeriDg, ChemlBtry, 



ilechanlcal EnglDeering, Geology, 



Electrical Engineering, Botany and Zoology, 



Mining Engineering, General Science, 



Architecture, Science for Teachers, 



Anatomy and Physiology (as a preparation for Medical Schools). 



For Descriptive Pamphlet apply to 



M. CHAMBERLAIN, Secretary, 

 N. S. SHALER, Dean. Cambridge, Mass. 



For Brain-Workers, the Weak and 

 Debilitated. 



Horsford's Acid Phosphate 



is without exception, the Best Remedy 

 for relieving Mental and Nervous Ex- 

 haustion; and where the system has 

 become debilitated by disease, it acts 

 as a general tonic and vitalizer, afford- 

 ing sustenance to both mind and body. 



Dr. E. Cornell Esten, Philadelphia, Pa., 

 says: " I have met with the greatest and most 

 satisfactory results in dyspepsia and general de- 

 rangement of the cerebral and nervous systems,, 

 causing debility and exhaustion." 



Descriptive pamphlet free on application to 

 Rumford Chemical Works, Providence, R. I. 



For sale by all Druggists. 



Beware of Substitutes and Imitations. 



D^oir IS Oexxts 



I will mail a finely finished original photo, 

 cabinet size, of Sioux Indian Chief, SITTINQ 

 BULL, with his Signature. Have 200 sub- 

 jects, all different, ofleading Western Indians.- 

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

 on selection. Give reference. Alter seeing sample you will 

 want others. Indian Costume, Ornament! and Weapons.. 

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

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

 I.. MT. SXILWEI.!., Deadwood, South Dab. 



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 ol 

 grain under each cover glass. 



WOOD SPECIMENS FOR GLASS 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. 



