346 ON PHYSICAL DATA 



Heat, or Caloric is the next subject of import- 

 ance, and is second to none in the Physicomathe- 

 raatical sciences, both in point of usefulness and 

 difficulty, which a close investigation into its 

 origin and nature will inevitably lead us to. 

 Whether material particles are kept asunder 

 by means of the repulsion of their caloric, or 

 by means of a property which the particle of 

 matter may possess, of changing the resultant of 

 its attractive energy at some point, not very distant 

 from itself, appears to be diflScult to determine. 

 This arises in consequence of the subtlety of the 

 operation, which entirely eludes the constant 

 exertion of our senses. The complete deter- 

 mination, however, of this question would be 

 attended with considerable advantage in the 

 consideration of molecular action. If a particle 

 of matter be surrounded with several smaller 

 particles of caloric, which repel each other, but 

 attract the particles of matter, whilst the particles 

 of matter repel each other, a material body subject 

 to pressure, large enough to overcome the repul- 

 sion of the caloric, would have its particles of 

 matter in closer contact or union, and consequently 

 would displace the particles of caloric which we 

 find to accord with observation. Now, if these 

 particles of caloric which are endued with a 



