38 SCIOPTICON MANUAL. 



open threads of the texture is lost, it is better, when 

 the instrument is invariably to bo placed in front, 

 to cover the surface with whiting or paper, keeping 

 it smooth by mounting it on a roller. When illumin- 

 ated from behind, the screen should be wet, to tighten 

 its texture and to make it translucent, and consequently 

 luminous on the side towards the spectators. It can be 

 wet and then stretched upon a frame, or first mounted 

 and then sprinkled to saturation. For home use, a sheet 

 may be stretched across the frame upon which the fold- 

 ing doors of most modern houses are hung, the doors 

 being thrown open at the commencement of the exhibi- 

 tion. A waxed screen is often recommended, but it is 

 little used on account of the difficulty of keeping it 

 smooth and clean. An unmounted screen can be quickly 

 put up in any room by procuring two strips of wood 

 about two inches square, and long enough to reach from 

 the floor to the ceiling ; a side of the screen is tacked 

 to each one of these strips, which are then stretched 

 apart, and wedged up tightly between the floor and the 

 ceiling. 



To widen the screen to more than nine feet, join the 

 added width to each side, rather than bring a seam into 

 the centre of the views. 



A fine picture from within, upon oiled muslin, stretched 

 upon a frame, made to fit a show window, is always 

 greatly admired by all the passers-by. Such a framed 

 oiled screen, on a small scale, can also be conveniently 

 used in parlors, or in the doorway leading out from the 

 company. 



Working behind the screen has in many cases decided 

 advantages, but the images can hardly be as bright by 

 transmitted light, and other things being equal, it is 

 better for the instrument to be in front. 



