OBJECTIONS ANSWERED. 11 



of an exhausted receiver, as in the experiments 

 of Sir Humphrey Davy, I answer that there is 

 an enormous amount of caloric locked up in a 

 state of chemical combination with ice, as shown 

 by the rapidity with which it melts frozen mer- 

 cury, nitrate of potass, chloride of lime, chloride 

 of sodium, and many other salts which have a 

 strong attraction for caloric. There is, therefore, 

 no good reason why caloric should not be sepa- 

 rated from ice by friction as well as from other 

 solid bodies. And it may be asserted with con- 

 fidence, that if all the latent caloric contained in 

 a pound of ice could be transferred to the same 

 weight of gold, silver, iron, or copper, it would 

 raise them to a red heat, and perhaps convert 

 them into flame, or incandescent luminous 

 vapour. 



That the particles of all bodies are surrounded 

 by an elastic medium, which prevents their actual 

 contact, is evident from their compressibility. 

 And that this medium is caloric is proved by the 

 facts already stated, that it augments the volume 

 of solids, liquids, and gases, which are again re- 

 duced to their former dimensions by abstracting 

 what was before added ; and by the large amount 

 of heat that is disengaged by friction, which is 

 transitive pressure, or by percussion, which is 

 sudden pressure; both of which cause condensa- 

 tion. It was estimated by Sir Isaac Newton, that 

 the pores of gold occupy about the same space as 



