SCIOPTICON MANUAL. 37 



oil is thoroughly drained out of the lamp-cup should the 

 instrument have to be repacked for transportation by 

 public conveyance. 



Standing behind the instrument, placed about breast 

 high as upon its box on a stand or table close down 

 the reflector jBT, pass in the slides at o c? with the right 

 hand, taking them out with the left as other slides take 

 their places. Focus the picture by the milled head e, 

 upon the screen, which may be distant sixteen feet, 

 more or less, as it is desired to have the scenes on a 

 larger or smaller scale. 



k (unlike the cut) is horizontal, and turns up to give 

 the appearance of a falling curtain on the screen. 



THE SCREEN. 



There can be nothing better for the projected pictures 

 than the white-finished, whitewashed, or white-papered 

 walls of many a lecture-room or dwelling. An appro- 

 priate space specially set apart and papered with white 

 wall paper, having an outline, say of a wide recess or 

 niche for statuary, is an inexpensive and not inelegant 

 fixture, on which to display before the assembled house- 

 hold, without waste of room or trouble in arranging, the 

 richest treasures of all the art galleries in Christendom. 

 The time is coming, when for purposes of demonstra- 

 tion and illustration in the lecture-room, this whiteboard 

 will rival the blackboard. 



The best material in the market for a movable screen 

 of good size, seems to be bleached sheeting of close 

 texture, but not very fine, twelve-quarters wide. This 

 gives us the material, nine feet square, for about two 

 dollars. It has the advantage of being available 

 whether the instrument is placed before or behind it. 

 As, however, every pencil of light falling between the 



