9 2 



THE ART OF PROJECTING. 



A small bunch of flowers, a statuette, the hand, etc., 

 are good objects to exhibit this property. 



Images can likewise be projected upon a screen by 

 means of the concave mirror. 



Fig. 69. 



At a distance six, eight, or ten feet from a screen 

 hold a lighted candle close in front of the mirror ; 

 slowly separate them : the image of the light will 

 appear inverted upon the screen, and much enlarged. 

 Advantage is taken of this property of the concave 

 mirror to project some phenomena, such as manome- 

 tric flames, etc., which see. 



CAUSTICS BY REFLECTION. 



A concave polished surface, like a strip of tin, two 

 or three feet long and an inch or two wide, bent into 



Fig. 70. 



