iv 



SCIENCE.— ADVERTISEMENTS. 



JDLIEN'S IMPROVED LAPIDARY LATHES 



For SLICING and POLISHING rocks, rainerals, fossils, 

 etc., and for GRINDING DOWN the same into micro- 

 scopical thin sections. Lathes, titted to foot or power, eon- 

 tain COMPLETE APPARATUS for the worlc. Send lor 

 illustrated catalogue. Rock sections for sale. 



GUSTAVUS D. JULIEN, 932 Bloomfield St., HOBOKEN. N. J. 



MARINE BIOLOGICAL LABORATORY 



Sappty Department — 1. Zoology — Preserved Material 



of all types of animals for class work or for the museum. 

 2. Botany— Pre.served material of Algae, Fungi, Liver- 

 worts and Mosses For price lists and all information ad- 

 dress GEO. M. GRAY, Curator Woods HoU, Mass. 



Ninth Revised Edilion. Published Jan. 190U. 



The Microscope and Microscopical Methods 



By SIMON HENRY aAQE, of Cornell University. 



Important changes have been made and the chapter on 

 Projection Microscope rewritten and more luUy illustrated. 

 New figures of American microscopes and apparatus. 

 Postpaid $1.50 as for the 8th edition 



COMSTOCK PUBLISHING CO., Ithaca, N. Y. 



The Rochlitz Automatic 

 WATER STILL 



works day ami night without at- 

 tention, and gives absolutely pure 

 and sterile distilled water at the 

 rate of half a gallon per hour. It is 

 especially adapted to hospital and 

 home use. Illustrated descriptive 

 circular sent post free. 



THE SCIENTIFIC SHOP, 

 322 Dearborn Street, Chicago. 



Getting Acquainted witli the Trees 



By J. HORACE McFARLAND. 



Illustrated, cloth, $1.50 net (postage 18c.) 



"Both delightful and companionable." 



— 7'imes and Despatch. 



THE MACMILLAN COM PANY, Publishers 



MAX KOHL, 



CHEMNITZ, SAXONY. 



MANUFACTURER OF 



Precision Mechanical Instruments 



Largest Establishment of its Kind. 



Furnishes as a specialty complete outfits for 

 Physical and Chemical Laboratories ; Physical 

 Apparatus and Instruments ; Apparatus after 

 Tesla, Hertz, Marconi, etc. Complete outfits for 

 X-Ray work. Purest radium bromid of 1,200,- 

 000 X activity. 



>o\' r:T>T V 

 INDUCTION COILS, with Changeable Self- 

 induction, which allow soft, medium hard 

 or hard X-Ray Tubes to be worked with 

 an electrolytic Interrupter with any current 

 Profusely Illustrated catalogue with 3,500 Illus- 

 trations, directions, quotations, references, etc., 

 in German, English or French furnished 

 without any charge. 

 World's Fair, Chicago, 1893: 2 Diplomas; 

 World's Fair, Paris. 1900: Gold Medal. Rep- 

 resented at the World's Exposition, St. Louis. 

 Selling agents, 



EIMER & AMEND 



205-211 Third Ave., New York City. 



The Care of a House 



A VOLUME OF SUGGESTIONS 



To householders, housekeepers, landlords, 

 tenants, trustees, and others, for the econom- 

 ical and efficient care of dwelling houses. 



By T. M. CLARK 



Fellow of the American Institute of Architects; Author 

 of "Architect, Otcner and Builder Under the Law." 



Cloth, 12mo, ^1.50 net (postage 14c.). 



"Indispensable to the householders." 



— Chicago Inter-Ocean. 



THE MACMILLAN COMPANY, Publishers. 



Leuckart=Chun Zoological Charts 



of 



Invertebrates and Chun Charts of Vertebrates 



Price, mounted on linen, Duty Free, $1.75 each 



German Pamphlet on request 



ARTHUR H. THOMAS COMPANY, importers and Dealers 

 Microscopes and Laboratory Apparatus 12th and Walnut Sts., Philadelphia 



