8CIOPTICON MANUAL. 29 



ANALYSIS OF THE SCIOPTICOW. 



The lenses, mountings, &c., Fig. 15, are shown in sec- 

 tion. What is left of the frame and cylinder, the lamp, 

 chimney, reflector, &c., are shown in perspective. The 

 parts are as follows : 



a J Front combination of the objective cemented together. 



c d Back combination separated by a ring. If the cells holding 

 these combinations are unscrewed and the lenses removed, they 

 must be returned in the same order and position as seen in the dia- 

 gram. There is no need of removing them. Even the outer sur- 

 faces of a and d will seldom need dusting if kept in a clean place 

 with the caps closed. They should not be fingered, and the brush 

 or fabric used for dusting them should be clean and soft. 



e Milled head for adjusting the focus. 



// Flange attached to the projecting wooden ring^^r. 



The tube here represented is a quarter-size portrait camera tube 

 of 4\ inches back focus, requiring an aperture in g h of 2| inches 

 in diameter. If a larger tube is used, the aperture in g h has to be 

 enlarged. If the back focus is more than 5 inches, the extension 

 front h k must be drawn out more or less from the main body, as is 

 shown in the diagram. If the focus is shorter than 3J inches, the 

 ring g g is removed, letting the flange/ back to A. 



h h h' "Wooden frame of the extension front ; h f sliding in a 

 groove within the body-frame I I. 



i Top of the hood covering light dispersed by reflection. The 

 near side is cut away to show the screen k ; the edge of the remain- 

 ing side is seen beyond k. 



k Is now modified into a horizontal lid, which shuts up over the 

 lens d, darkening the picture on the screen like a falling curtain. 



I I Portion of the wooden frame, the rest being mostly cut away 

 to show the lamp, and how the extension front slides in its groove. 



m Claw attached to the front foot. 



n Flange under the back foot. On the top of the Sciopticon 

 case, or box in which it is carried, and which can be placed upon a 

 stand or table to elevate the instrument to proper height while in 

 use, are two round-headed screws, slightly raised, and at the dis- 

 tance apart of m n ; m clings to one, and n slips under the other, 



