ATTRIBUTES OF A PRIMARY CAUSE. 17 



it, would destroy the repulsive power of their 

 particles. And as we have seen, that without 

 caloric, they could have no power of motion, it is 

 evident that they could neither approximate nor 

 recede from one another ; consequently, that both 

 attraction and repulsion are modified effects of 

 one and the same agent. Moreover, if it can be 

 proved that this agent is every where present in 

 the pores of bodies, as in the stellary spaces and 

 cannot be traced to any more comprehensive 

 principle it must be allowed to possess all the 

 attributes of a primary efficient cause. For, no- 

 thing can merit the title of a vera causa, unless 

 it be something which has the power of moving 

 itself, and of generating motion in other bodies. 



It is equally evident, that whatever the cause 

 of attraction and repulsion may be, it must de- 

 termine all the phenomena of cohesion, chemical 

 affinity, crystallization, elasticity,* decomposition, 



* If the particles of the atmosphere and other bodies were not 

 surrounded by caloric, there could be no vibrations, (in which 

 heat has been supposed to consist,) therefore no sound. And 

 here it is worthy of notice, that the velocity with which sound is 

 propagated through different media, is directly in proportion to 

 their elasticity, ceteris paribus. For example, it travels through 

 the atmosphere when at the temperature of 32, at the rate of 

 1090 feet per second; but when at 62, it travels 1125 feet per 

 second. It also moves at the rate of 3375 feet per second through 

 hydrogen gas, which contains a much larger amount of caloric 

 around its particles, than the same weight of atmospheric air, or 

 any other gas, as will be shewn hereafter. In accordance with 

 the above facts, it is well known that sound is transmitted more 



