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SCIENCE 



New Series. 

 •Vol. VII. No. 181. 



Friday, June 17, 1898. 



Single Copies, 15 cts. 

 Annual Subscription, $5.00 



General Electric Co.s 



New X=Ray Tube 



WITH AUTOMATIC VACUUM REGULATOR. 



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. 



Eillsoii Decoialive anil iQlQlatuie LaniD DepailniiiQt, 



(GENERAL ELECTRIC COMPANY,) 



HARRISON, N. J. 



Complete W\m2\ Catalogue. 



186 pages, 40 splendid engraTin^s. Con- 

 tains a table giving name, composition and 

 form of all kuown minerala, with 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, 

 collectors, mining experts, chemists, and others. Postpaid; Paper, 35 cents; Cloth, 50 cents; Calf, interleaved, 81.00. 



Established 1876 



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



COLLECTIONS OF MINERALS FOR STUDY OR REFERENCE. CABINET SPECIMENS. GEMS. 



^^^^^^ Biddle's Bulletin for June -^^^^^^^ 



My business is to act as an intermediary between the manufacturer and purchaser of Scientific ' 



Apparatus. In many respects I believe my methods of conducting these relations are unique, and i 



I know that they are successful. My connections are extensive, so that to keep in touch with my \ 



customers — to explain periodically what I am doing — I have started the publication of an 8-page ' 



monthly. It is sure to be interesting to a large proportion of those who read this ad. Consequently i 



I want you to write now for a sample copy of the June number. J 



Subscription, 50 cents a year. * 



Electrical and Scientific Instraments, 

 Psychological Apparatus. 



Projection Lanterns, etc. 



James G. BiDDLE, Publisher, 



909 Drexel Building, Philadelphia. 



