PROJECTION MICROSCOPE 



\CH. IX a 



PROJECTION OF OPAQUE OBJECTS 



$ 428. Episcope. For the projection of opaque objects like anatomical prep- 

 arations, figures in books, coins or indeed any opaque object an apparatus on the 

 principle of the one figured (Fig. 214) is used. That is, a powerful light is thrown 

 upon the opaque object and the rays reflected from the object are then projected 

 upon the screen by an objective as for a lantern slide. As the objects are mostly 

 in a horizontal position the objective points directly upward, and the rays from it 

 must be made horizontal by means of a 45 degree mirror or prism. 



This apparatus is very old. Its first name was "aphengescope" or opaque lan- 

 tern. Now it is called an episcope, or megascope, and if for both opaque and 

 transparent objects (Fig. 214) it is designated as an epidiascope. 



FIG. 214 B. 



FIG. 214 B. Spencer- Winkel Mechanical Stage, New Form. In this new 

 form of the Spencer- Winkel mechanical stage the milled heads for working the 

 screws are placed close together so that they can be turned without changing the 



