206 FLIPPY. 



"We look around us upon a spring or summer day, and 

 see, as we think, greenness in the grass, and other beauti- 

 ful colors in the flowers. Illusion ! the colors are sensa- 

 tions in our minds. 



The sense of sight is perhaps the most fruitful source of 

 our illusions, but the other senses are in some cases equally 

 deceptive. We hold our hands before the fire and experi- 

 ence a sensation of warmth, and we imagine that there is 

 warmth in the fire; but a moment's reflection will show 

 us that warmth is a sensation, and that there can not pos- 

 sibly be a sensation of any kind in fire. It is sometimes 

 said that there is no heat in fire, and this is true if we mean 

 by heat the sensation of heat such as we ourselves experi- 

 ence by the action of fire. But the word heat has a double 

 meaning ; sometimes it refers to the feeling which we ex- 

 perience, and sometimes to that property or condition of 

 the external body that causes that feeling. In the former 

 sense it is true that there is no heat in fire. 



The word warmth is more exclusively confined to the 

 sensation, and therefore we can say in a more unqualified 

 manner that there is no warmth meaning no sensation of 

 warmth in fire. It is true, we sometimes speak of water 

 being warm, and it is perfectly right so to speak; only 

 when we do so it is important, in a scientific sense, to un- 

 derstand that what we mean is that the water is in such a 

 condition in respect to temperature as to create the sensa- 

 tion of warmth in us when we put our hands into it, not 

 that it feels any sensation of warmth in itself. 



It is plain that there can be no sensation of any kind in 

 the fire or in the water, an idea which is quaintly expressed 

 in the well-known distich 



"There's no warmth in the fire that heats yon, 

 Than there's ache in the stick that beats you." 



In the same manner, it is true that there is no sound in 



