Notiee to Rtf«rf«r.— When you finish reading 

 this magazine, place a 1 cent stamp on this notice* 

 mail the magazine, and it will be placed in the 

 hands of our soldiers or sailors destined topro* 

 ceed overseas. No wrapping—No Address. A* 

 5. Burleson, Postmaster-Geaeral, 



SCIENCE 



New BsBiBa 



Vol. XLVII No. 1226 



Friday, June 28, 1918 



BiNQLi Copies, IS Cra. 

 Anndal Sdbsoriftiom, IS.( 



Bausch & Lomb 

 Balopticon 



The Perfect Stereopticon 



Invaluable for iaHtruction and lecture work 

 — an ideal projection lantern for class room, 

 laboratory or auditorium. 

 Models for either lantern 

 slides or opaque objects 

 (photo prints, post cards, 

 specimens, etc.) or both. 

 Equipped with the new gas- 

 filled mazda lamp, absolutely 

 automatic. More complete 

 ., _ , ,,»». models for microscopical and 



>B«iiiiii«i I ki all known forms of optical 



Combined Balopticon projection. 



Because of the demands made upon our resources for some of the government's 

 mget important military needs, we are unable to make Balopticon deliveries for 

 the present. While proud to be of service in this world crisis, we shall expect 

 to serve our other patrons even more efficiently than before, when the world is 

 again at peace. 



Bausch ^ Ipmb Optical (q. 



552 ST. PAUL STREET ROCHESTER, N.\; 



N«w York 



WashlriKton 



ChlcaKO 



San Franciaoo 



Leading American Makers of Microscopes, Photomiaographic and Projection Apparatus 



(Balopticons), Photographic and Ophthalmic Lenses, Stereo-Prism Binoculars 



and Other High Grade Optical Products 



