1^1 



SCIENCE 



New Series. 



-Vol. VIII. No. 185. 



Friday, July 15, 1898. 



Single Copies, 15 cts. 

 Annual Subscription, $5.00 



General Electric Co.'s 



New X=Ray Tube 



WITH AUTOMATIC VACUUM REQULATOR. 



Simple. Efficient. Long-lived. Cannot run too high in vacuum. 



Roentgen Ray Apparatus, catalogue No. 9,050. Minia- 

 ture, Candelabra, Decorative Lamps, catalogue No. 9,044. 



ESlsoii Decorative aDii iniiilatuie Lamn DepaitDieiit, 



(GENERAL ELECTRIC COMPANY.) 



HARRISON. N. J. 



Complete Mineral Catalogue. 



186 pages, 40 splendid engravings. Con- 

 tains a table giving name, composition and 

 form of all known minerals, witti a supple- 

 ment bringing the work up to date. Metallic 

 classification showing what minerals contain 

 each element. Alphabetical index of names. Lists giving the specimen values of minerals, etc, etc. For teachers, students, 

 collectorSj mining experts, chemists, and others. Postpaid ; Paper, 35 cents; Cloth, 50 cents; Calf, interleaved, $1.00. 



DR. A. E. FOOTE, 1317 Arch Street, Philadelphia, Pa., U.S.A. 



COLLECTIONS OF MINERALS FOR STUDY OR REFERENCE. CABINET SPECIMENS, 



Established 1876 



MAX KOHLi^ Ghcninitx^ Crea^many^ 



FIRST EUROPEAN MAKER OF 



Physical and Ulectrical Instruments 



Special Manufacturer of Koentgen X-Kay Outfits. 



Apparatus for Experiments witli Currents of HJgli Frequence and Tension. 



Apparatus for the Experiments according to Hertz. 



Apparatus for Marconi's Wireless Telegraplij', 



Price List No. 10 of Physical Instruments ; nearly 400 pages and more than 1300 engravings (in German, English 

 and French). Special List of X-Ray Apparatus containing numerous testimonials as well as estimates for complete 

 outfits, explicit directions for use, etc., in English language. 



S^ REFERENCES FROM LEADING EXPERTS. -"^^ 



Represeniative: Messrs. EIMER & AMEND, 205-211 Third Avenue, New York. 



