Mater an& 1fce, 181 



upward until it reaches the boiling point, 

 where it is again arrested. And no matter 

 how much heat is applied to the boiling water, 

 if in an open vessel, the thermometer remains 

 the same until all the water is evaporated. 

 Here are two curious facts, and they are facts 

 that, if we can master them, will serve as a 

 key to the understanding of much that is mys- 

 terious in nature. 



It will be our endeavor to give the reader a 

 mental picture of what is taking place during 

 the time the ice is melting and the thermom- 

 eter is stationary. Do not suppose that you 

 can understand this, even so far as it is under- 

 standable, by a casual reading without 

 thought. No man was ever yet able to present 

 a picture to the mind of another, however 

 clearly and simply it may be done, unless that 

 other mind is receptive. When a photog- 

 rapher trains his camera upon an object, how- 

 ever intense the light may be and however 

 clean-cut the picture that is thrown upon the 

 plate in the camera, unless that plate is prop- 

 erly sensitized so that the picture may be im- 

 pressed upon it, all of the other conditions are 

 in vain. The reader is always a part of the 

 book he is reading. 



