SCIENCE 



New Series 



Vol. LVI, Xo. lU-2 



Friday, August 18, 1922 



Annual Subscription, $6.00 

 Single Copies, 15 Cts. 



Bausch & Lomb 



Drawing 



Can be Used in 



Both Vertical 



and Horizontal 



Position 



To meet the requirements of those engaged i i research or reconstruction work, as well as for 

 regular routine student use, this new Drawing A jparatus has been designed. It can be used in a 

 horizontal position, as illustrated, or vertically. 



The microscope is of special design, with a re iiovable body tube to permit the use of both low 

 and high power objectives. The stage, which w 11 accommodate large slides, -is so arranged that 

 the slide can be held on either side. ''^"--^iiorr. 



Either a concentrated filament Mazda or Tu igs-arc lamp can be used as the light source. 



Write for complete description and prices 



Bausch & Lomb Optical Company 



409 St. Paul Street, Rochester, N. Y. 



Ne 



York 



Washington 



Chicago 



San Francisco 



London 



LeacLng American Makers of Optical Measuring: Instruments, Photomicrographic Apparatus, Photographit 



Lenses, Microscopes, Projection Apparatus (Balopticons), Ophthalmic Lenses and Instruments, 



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



Binoculars, Telescopes, Magnifiers, Automobile Lenses and other High-Grade 



Optical Products. 



