SCIENCE 



New Bebibs 



Vol. XXXVII. No. 9S2 



Friday, March 28, 1913 



SiNGLB CkJPIIS, 15 CT8. 



Annual Bubsobiption, t&.CC 



Progressive Teachers of Science 



appreciate and value the aid given them by a perfect projection in- 

 strument One easily and rapidly changed from any one form of 

 projection to any other—one that is efficient, durable and economical. 



K&uscK [om 



Convertible 



^alopticon 



The Superior Quality 

 of Bausch (^ Lomb len- 

 ses, microscopes, field 

 glasses, projeclion ap- 

 paratus, engineering 

 and other scientific in- 

 struments is the product 

 cf nearly Sixty Years 

 '•/ Experience. 



as Here illustrated, projects interchangeably lantern slides, opaque illustrations and objects, in 

 vertical and horizontal plane as may be desired — microscopic objects, polarized light and 

 physical experiments. Every known form of projection is possible. The lantern may be 

 bought in simpler form and built up as desired. The dark chamber and object holder are 

 so constructed that large objects of varying thicknesses can be very conveniently put in place 

 and automatically brought into correct position. 



Descriptive Circular 15 D sent on request. 



Bausch ^ [pmb Optical (^. 



NEW YORK WASHINGTON CHICAGO - SAN FRANCISCOj 



LONDON liOCHESTEa, N.Y. •^•^^'^•^^^^^ 



