SCIENCE 



New Series. 

 VOL.Vn. KO. 162. 



Feiday, February 4, 1898. 



Single Copies, 15 CTS. 

 Annual Subscription, $5.( 



General Electric Co.s 



FLUOROSCOPES 



PlatinO'Cyanide of Barium, or Tungstate of Calcium Screens. 



NEW X=RAY TUBE 



WITH AUTOMATIC 



VACUUM REGULATOR. 



EFFICIENT. LONG-LIVED. 



ROENTGEN RAY APPARATUS of all kinds. 



Catalogue No. 9050. 



Candelabra, Miniature and Decorative Lamps. 



Catalogue No. 9041. 



EillsDQ Decorative anil pilnialnre Lamp DeDaitineiit, 



(GENERAL ELECTRIC COMPANY,) 



HARRISON, N. J. 

 BEECHER TRILOBITE WODELS. L^^l^-rror^^rrsZ: 



used by Prof. C. E. Beecher to produce these models, 2}^ times natural size, whicli 

 show both ventral and dorsal surfaces with full details of all the appendages. 

 Either on separate plaques or both on one plaque 4J^ x &% inches of tinted, hard- 

 ened plaster with accompanying descriptive label, price, S5.00 ; postage 20 cents. 



Ward's Xatural Science Establishment, 



IS to 2S College Ave., Rochester. N. Y. 



New Catalogues of Scientific Apparatus. 



No. 245. " Standard Apparatus for Electrical Meas- 

 urements. ' ' 

 No. 250. " Ideal Projection Lanterns and Improved 



Focusing Electric Lamps." 

 No. 255. "The Eosa Curve Tracer." 

 No. 260. "Net Price List of X-Eay Apparatus." 

 No. 265. "The Rowland Electrodynamometer." 



No. 270. ■' A Few Specialties for Colleges and 

 Schools." 



No. 275. "Condensers, — Standard and Commer- 

 cial." 



Cat. A. " The Chloridu Accumulator. " 



Cat. X. "Weston Standard Voltmeters, Ammeters, 

 Wattmeters, Etc." 



Write for such as interest you, but do not think that this list represents the entire scope of my trade. 

 I am a business helper to the buyer of scientific apparatus. I make a specialty of " Duty Free " Importations 

 from Europe. It will cost nothing to ascertain it I can assist you. Correspondence solicited. 



JAMES Q. BIDDLE, 909 Drexel Building, Philadelphia. 



