INTRODUCTION. Vll 



free space between, open above and below. Its front band 

 presents a good bearing for resting the slides against, 

 without exposing the glass to be scratched by them. Its 

 two lenses are removable, while yet they are securely held 

 in concentric cells by wire rings sprung into grooves. 



8. The Cylindrical Form of the body is suited 

 to the size and shape of the condenser at one end, and the 

 reflector at the other, with opening flaps, setting it above 

 the wooden frame, giving a lamp chamber and a condenser 

 chamber both separate from the flame chamber, and allow- 

 ing unobstructed air passages without escape of light. 



9. The Stage (o) is unobstructed by a bulky sliell 

 wider than itself, is under the hand of the operator stand- 

 ing behind and looking toward the screen, and allows 

 the pictures to slide horizontally into place, one after 

 another, without exposing a blank disk. 



The catch drawn out from the under side of the stage, 

 and turned back almost out of the way, is intended to 

 stop the slide in its proper position, but not to interfere 

 with its being moved smoothly along and out by the 

 incoming slide, when slipped forward from the catch by the 

 left hand. 



The catch pushed back into its sheath, leaves the stage 

 entirely unobstructed for those who prefer to adjust the 

 slides by hand only, and for other than wooden slides. 



The use of stops is the more necessary with a pair of 

 instruments, as it is essential to a proper effect that the 

 dissolving views should occupy exactly the same place on 

 the screen without any readjustment after the dissolving 

 becomes visible. 



10. The Extension Front is readily removed, to 



