SCIENCE 



New Series 



Vol. XXXVII. No. 943 



Friday, Januaey 24, 1913 



SiKQLK Copies, 15 Cts. 

 Annual Subscription , 85.00 



Several points of superiority render the 



Bland I I 



ausch lomD 



Convertible 



Balopticon 



the best projection apparatus obtainable for work in the lecture room and 

 laboratory. Here are some of these features ; 



It may be bought in simpler form and built 



up la 



The Superior Qualify 



vfBausch ^Lomh lew 

 ses, micToscopest fieit^ 

 glasses, projection ap' 

 paratus, engineering 

 and other scientific in- 

 struments is the product 

 of nearly Sixty Years * 

 E>xperience, 



1. It renders possible'every kno'wn form of op' 

 tical projection — lantern slide, opaque, micro 

 scopic, vertical, polariscopic and spectroscopic. 5. 



2. It provides a convenient and instantaneous ^*^"* 

 interchange between all forms. "^/' 



3. Its different parts are easily interchange 

 able, making it an easy matter to rearrange appa- j 



Opaque obje 

 ire.orsmaller- 

 zontal position- 



i desired. 



and illustrations — 7^^ inch 

 n be projected in ver/(ca/ or 

 nth the use of one or two 

 TTor at all 



rigid andaccurateinallad- 

 le time simple and easy of 



Send for Descriptive Catalogue 15 D, 



Bausch ^ Ipmb Optical ©. 



NEW YORK WASHINGTON CHICAGO -w SAN FRANCISCO 



LONDON liOCHESTEn, N.Y. fRANKrORT 



'c,'^ 



JAN 241913 



