144 SCIOPTICON MANUAL. 



CHAPTEE XL 



NOVEI/TIES. 



THE CHIMNEY CAP of the Sciopticon now telescopes 

 into its base, so as to give added length and greater 

 draft when drawn up. It should not be elongated, how- 

 ever, when the instrument is first lighted especially if 

 the wicks are not well saturated with oil but when 

 well under way, the added length, with a correspond- 

 ing turning up of the wicks, gives greater brightness, 

 and more effectually draws off the heat. 



THE SCIOPTICON CURTAIN. Turning the milled head 

 at either side, gives the appearance upon the screen of 

 a curtain rising, or falling, thus handsomely opening 

 or closing an exhibition. It may also be temporarily 

 closed at any time, to allow the attention to be directed 

 to other exercises. 



The process of changing the pictures may be hidden 

 from view by shutting off the light with the left hand; 

 then pushing the out-going picture into the left hand 

 by sliding another into its place with the right; and 

 then flashing on the light with the right hand ; all of 

 which may be sooner done than said. In any change of 

 programme the awkwardness of showingthe "full moon," 

 or the disk without a picture, may always be avoided by 

 using the opaque curtain. 



This curtain also serves as a back cap for the object- 

 ive, protecting the back lens from dust and light when 

 not in use, as the front cap protects the front lens. 



