SCIENCE 



}fSVT SBBIB3 



Vol. LI, No. 1825 



Friday, May 21, 1920 



SiNOLS Copies, 15 Cts. 

 Annuai. SuBacBiPTioK, SS.ra 



BauscK'bmb 



[Vficroscbpes 



TKe Accepted Standard 



FS2 Model with two 

 objectives in revolving 

 nosepiece and one in 

 eyepiece. $64.00 



When }'ou buy a Bausch & Lomb Microscope you buy 

 the cumulative results of 66 years of optical endeavor and 

 manufacturing experience. 



During that period we have developed every optical 

 refinement and mechanical improvement demanded b}' the 

 practices of modern microscopy. 



Our optics — designed, tested and controlled in manufacture by our 

 own Scientific Bureau — have withstood the most exacting, long-time tests 

 of research laboratories. 



Our side line adjustment is of the most approved lever type — highly 

 sensitive and durable. 



There is a Bausch & Lomb model for every microscopical require- 

 ment. Write for our new complete catalog. 



Bausch ^ Ipmb Optice"! Q- 



409 ST. PAUL STREET 



NEW YORK WASHINGTON 



ROCHESTER, N. Y. 



CHICAGO SAN FRANCISCO 



Leading American Makers of Photographic Lenses, Microscopes, Projection Apparatus, 

 (Balopiicons), Ophthalmic Lenses arid Instruments, Photomicrographic Apparatus, Range 

 Finders and Gun Sights for Army and Navy, Searchlight Reflectors, Stereo-Prism 

 Binoculars, Magnifiers and other High-Grade Optical Products. 



