SCIENCE 



New Seeies 

 Vol. L, No. 1295 



Friday, October 24, 1919 



Single Copies, 16 Ots. 

 Annual Sdbscription, S6.00 



Combined Balopticon for Lantern Slides and Opaque 

 Objects. Price, $150.00 



^ausch^lomb 



BALOPTICON 



THE PERFECT STEREOPTICON 



with its technically cor- 

 rect optics and brilliant 

 illuminating system will 

 give you the most satis- 

 factory results possible to 

 obtain on the screen — 

 whatever the form of pro- 

 ject on. There is a model 

 for every purpose, simple 

 in construction and al- 

 most automatic in oper- 

 ation. 



Our greatly enlarged facilities, now being released from 

 important war work, will enable us to increase production 

 in this line. Under present adjustment conditions, how- 

 ever, it will be to your advantage to anticipate your re- 

 quirements as far ahead as possible. 



Write for catalog, with revised price list, and enter 

 your order now for fall delivery. 



Bausch ^ Ipmb Optical (^- 



New York 

 Chicago 



Washington 

 Rochester, iM. Y. 



San Francisco 

 London 



Leading American Makers of Photographic Lenses, Microscopes, Projection 

 Apparatus (Balopticons), Ophthalmic Lenses and Instruments, Photomicro- 

 graphic Apparatus, Range Finders and Gun Sights for Army and Navy, 

 Searchlight Reflectors, Stereo-Prism Binoculars, Magnifiers and other High- 

 Grade Optical Products. 



