Our Microscopes, Microtomes, Laboratory Glass- 

 ware, Chemical Apparatus, Chemicals, Photo 

 Lenses and Shutters, Field Glasses, Projection 

 Apparatus, Photo-Micro Cameras are used fay 

 '^leading Lab- ,™_____ oratories and 

 Gover'nt Cep'tsB 9 Round the World j 



§■ 



Catalogs 



Frea 



Bausch & Lomb Opt. Co. 



A Rochester, N. Y. v 



New York Chicago Boston Frankfurt, G'yj 



Photo Lenses! 



and Shutters of every 



kind for all purposes ; 



Professional, 



Amateur, Process. 



Sold Round the World on all 

 Cameras. Catalogue free. 



iBausch & Lomb Opt. Co.^ 



ROCHESTER, N. T. 

 New York Chicago Boston 



RADIUM 



From the Curie Laboratory for Experimental Use. 

 Radium 7000 Activity, 10 milligrams, in glass 

 tube, $17.50. ltadium 10<MM> Activity, 10 milli- 

 grams, in glass lube, $20.00. Larger quantities at cor- 

 responding rates. Prompt deliveries. The Spin- 

 thariscope, invented by Sir William Crookes, shows 

 brilliantly the properties of radium. Complete with 

 particle of Radium, postpaid, $9.00. 



RADIOGRAPHIC LANTERN SLIDES 



from most remarkable negatives taken by means of 

 Radium. Send for circulars. Special rates to schools on 

 Microscopes, Stereopticons and Educational Lantern 

 Slides. Agents for Leitz, Zeiss and Beck Microscopes. 



WILLIAMS. BROWN A EARLE. 

 Department N 918 Chestnut St., Philadelphia. 



BSBB 



BARGAINS 



in Second Hand 



Microscopes, Lenses, 

 Cameras, etc. 



GOOD WORKING ORDER AL- 

 WAYS GUARANTEED. 



Send for SPECIAL LIST 



just issued. 



EDWARD PENNOCK 



3608 Woodland Avenue, 



PHILADELPHIA. 



