CH. IX] PROJECTION MICROSCOPES ON THE MARKET 307 



FIG. 171. NEW STYLE CONVERTIBLE BALOPTICON FOR MICROSCOPE, LAX- 

 TERN-SLIDE AND OPAQUE PROJECTION, AND FOR THE PROJECTION OF 

 LARGE TRANSPARENCIES IN A HORIZONTAL POSITION. 



(Cut loaned by the Bausch & Lomb Optical Co.). 



As shown in the picture, this instrument is designed for projecting all kinds 

 of objects either in a vertical or in a horizontal position. For the large trans- 

 parencies the object is placed on the broad plate beneath the objective. 

 Immediately under the object is the condenser lens of 20 cm. (8 in.) diameter, 

 thus making it possible to project X-Ray plates, brain sections, etc., 20 cm. 

 (8 in.) in diameter. A mirror in the dark chamber directs the horizontal beam 

 from the first element of the condenser vertically as in all projection of this 

 kind. 



For the large transparencies the projection objective is in a vertical position 

 with mirror to reflect the light to a vertical screen and to overcome the left to 

 right inversion. 



FIG. 172. UNIVERSAL BALOPTICON FOR OPAQUE OBJECTS, MICROSCOPIC 



OBJECTS AND FOR LANTERN SLIDES OR OTHER TRANSPARENT OBJECTS 



IN A VERTICAL OR A HORIZONTAL POSITION. 



(Cut loaned by the Bausch & Lomb Optical Co.). 



For the opaque projection and lantern slides in a vertical position see fig. 106. 



For lantern slides or other transparent objects in a horizontal position the 

 arrangement for vertical slides is pushed back, and this brings the condenser 

 lens and plate for supporting horizontal objects over the opening. The same 

 mirror is used for directing the beam of light upward as for the vertical slides. 



