SCIOPTICON MANUAL. 



CHAPTEK I. 



THE CAMERA OBSCVBA. 



A picture formed by rays of light from the several 

 parts of an object as seen at A (Fig. 1), is called an 

 image ; and the cham- 

 ber in which it is 

 formed, and from 

 which all light is ex- 

 cluded, except what 

 enters a small hole 

 as at S, is called a 

 camera obscura. 



This dark chamber 

 claims attention here 

 because its properties, which are common to the eye, 

 the Sciopticon, and all forms of the camera, are seen on 

 a broad scale, and may be readily verified by inexpensive 

 experiments. To avoid confusion the pencils of light 

 are represented in Fig. 1 without marginal rays need- 

 ing to be focused by a convex lens. Explaining the fol- 

 lowing properties in connection with a diagram without 



2 



1. 



