SCIENCE 



New Series. 



Vol. VIII. No 197. 



TTRTnAv Optotsft? 7 1 SQS single copies, is cts. 

 JK1"AY, WCIOBER i, iOt>0. Annual Subscbiption, 85.00 



General Electric Co.s 



FLUOROSCOPES 



PIatino=cyanide of Barium, or Tungstate of Calcium Screens. 



NEW X=RAY TUBE "^'^ ^^^^^^.c 



VACUUM REGULATOR. 

 EFFICIENT. LONG-LIVED. 



ROENTGEN RAY APPARATUS of all kinds. 



Catalogue No. 9050. 



Candelabra, Miniature and Decorative Lamps. 



Catalogue Ho. 9044. 



EUlsoQ Decoiatlve aoil piiiilatuie Lamp DepaitDiiiiit, 



{GENERAL ELECTRIC COMPANY.) 



HARRISON. N. J. 



l9A6liXS £LX XJXSCOU.U.X < lectlon of shells has been 

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Our new SHELL. CATALOGUE, 170 pages, over 200 illustrations, de- 

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WARD'S NATURAL SCIENCE ESTABLISHMENT, ROCHESTER, N. Y. 



Apparatus for Psychological Laboratories 



Last May I issued a revised catalogue of Psy- 

 chological Apparatus, No. 300. Every college 

 professor interested in the subject should write 

 for a copy, as it is free to such. 



I have equipped some of the best American labora- 

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 by Willyoung &, Co., but in addition import from Cam- 

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 Petzold, Zimmerman and other prominent European 

 =I\lagnetic Fork, S5a. makers. Correspondence requested. 



BIDDLE, 909 Drexel Building, Philadelphia, Pa. 



