ON THE EFFECTS OF ttEAt. 97 



granted, it follows, that every particle of matter will be 



surrounded with an atmosphere of caloric ; the density of 



which will increase, as the distance from the centre of the 



particle decreases ; and this probably in a duplicate ratio. ' 



Hence, no two particles of matter can touch each other*i 



This is a fact, which was proved long ago by Sir L 



Newton. 



When the attraction of the particles of a body for each Constitotion 

 other is so great, that the distance between them is loss ° *° ' "* 

 than the particles themselves, all motion among them must 

 be prevented, and the body, consequently, will be solid. 

 But, if the distance between the particles of a body be 

 greater than the particles, yet, if the density of the atmos- 

 pheres, which surround them, be very great, all motion 

 luay still be prevented ; for it is evident, that they can only 

 be moved by compressing the atmospheres; the density of 

 which may be too great to admit of this compression by any 

 force less than what would destroy the texture of the body: 

 in this case, also, the body must be solid. It is probable* 

 that the first case never occurs: the density of the atmos- 

 pheres, therefore, is the cause of solidity. Hence the 

 particles may be at a great distance from each other, and 

 the specific gravity of the body vary little. The size^ form, 

 and weight of the particles, (all of which probably vary,) 

 must also be taken into consideration. 



Sir I. Newton supposed, that the particles of fluids were Constitution 

 spherical ; and in this manner he accounted for the °^*^"^^*" 

 facility with which they yield to the slightest impulse. 

 Bu-tifthe particles of solids be of different forms, (which 

 may be considered as proved by Haiiy,) it is difficult to 

 conceive how they can be converted into spheres by the ap- 

 plication of heat. But it is easy to conceive, that the accu- 

 mulation of caloric will augment the atmospheres, and 

 thus cause them to approach to the form of spheres, let the 

 form of the'particles be what it may. The same effect will 



* When I say, that no two particles of matter can touch each other 

 I speak of those which are homof:eneal. It is possible, I had almost 

 said probable, that the atoms of oxiKen and hidrogeny in the state of 

 water, do touch each other. This may perhaps help to distinguish cli©. 

 raical combination from cohesion, &c. 



VoL.XXXI.— Feb. IS12. H be 



