THE CAMERA OBSCUKA. 



6. Another variety of mounting for cameras is shown in fig. 4 

 (p. 203). This, which is one of the most portable forms of the 



instrument, consists of a rectangular case, composed of two parts, 

 one of which slides within the other like a drawer ; in one end is 

 placed the lens B, in the other a plain mirror M, inclined at an angle 

 206 



