86 THE ART OF PROJECTING. 



right, and throws a powerful beam upon it. It being 

 dressed in white, a good deal of the light is reflected 

 from it in all directions, and a part of that which falls 

 upon the glass at r will be again reflected toward /, 

 when it will appear as if it came from c, as far back of 

 r as b is front of it. All of the lights in the room are 

 turned down except that in the lantern, and none of 

 that is permitted to fiiid its way into the room save 

 what is reflected from the ghost. There is black cloth 

 for absorbing the light back of b. The person who 

 holds conversation with the phantom is at d, but of 

 course he cannot see what those see who are at /, or 

 near that line, and all his movements are guided by his 

 knowledge of the necessary position of the reflection. 

 In his book, Cyclopaedic Science Simplified, Professor 

 Pepper has given several methods for showing such 

 spectra. The skeleton, the talking head, and others 

 are thus exhibited. 



The extensiveness of the preparation for exhibiting 

 the ghost will prevent most experimenters from at- 

 tempting it ; but if the teacher would care to show the 

 principle, he will find the following a cheap and effect- 

 ive one, which he can extemporize with what materials 



Fig. 63. 



