10 SCIOPTICON MANUAL. 



a lens, may help to correct the common impression that 

 these properties and a convex lens arc inseparable. 



THE INVERTED IMAGE. 



Of the rays of light proceeding in all directions from 

 every point in the object , as from all illuminated 

 objects, just an assortment, that is to say a pencil from 

 each point will enter the hole at S, just in lino to fall in 

 reverse order upon the screen J., forming an inverted 

 image. 



The picture results from admitting just an assortment 

 and excluding all the rest. 



COLOR AND SHADING. 



Light from each of the several parts of the object B 

 illuminates with its peculiar color and relative intensity 

 each corresponding part of the imago, so that it is seen 

 in natural light and shade, and in natural colors. The 

 photographer can fix the relative shading, but ho cannot, 

 as yet, fix the colors. 



MOTION. 



If, for example, the bird moves to a higher porch, the 

 pencils of light will fall to a lower place on the screen, 

 and so any movement of the object which alters the 

 direction of the pencils of light, will give a reverse 

 movement to the image. 



SIZE. 



By inspecting the angle of extreme rays it will bo 

 seen that the imago in this case is smaller than the ob- 

 ject, because it is nearer the aperture; so in all cases, 

 the relative size of the image depends on its relative 

 distance from the aperture. 



