OBJECTIONS ANSWERED. 9 



keeps the particles of solids, liquids, and gases, 

 at a distance from each other while quiescent, or 

 free from vibratory motion.* And it is worthy of 

 special notice, that caloric is disengaged by pres- 

 sure, friction, or percussion, only so long as 

 bodies undergo condensation. For it has been 



* It was supposed by Bacon, that the essential nature of heat 

 is motion, and nothing else, because it accompanies the motion 

 of friction, percussion, combustion, ebullition, violent exercise, 

 &c. Count Rumford was led to adopt the same opinion from 

 the following experiments : Into a cannon weighing 113 Ibs. and 

 cast solid, he caused a hole to be bored 3*7 inches in diameter, 

 and 7'2 inches in depth. Into this hole, he introduced a blunt 

 steel borer, that was made to rub against the bottom by horse 

 power, with a force equal to about 10,000 Ibs. avoird., the cylinder 

 being turned at the rate of thirty-two times per minute. At the 

 expiration of thirty minutes, when the cylinder had made 960 

 revolutions about its axis, its temperature was found to have 

 risen from 60 to 130 F. In another experiment, the cylinder 

 was wrapped round with flannel to prevent the loss of heat, and 

 inclosed in a wooden box containing 18*77 Ibs. of water, which 

 at the beginning was at the temperature of 60. After the ex- 

 periment had proceeded for an hour, it was raised to 107, in 

 thirty minutes more, to 142, in two hours, to 178, and in 

 two hours and a half, to 210. At the close of the experiment, 

 he found that 4145 grains of metallic dust and scales had been 

 detached from the bottom of the cylinder by the rubbing of the 

 borer, or above eight ounces. And as he found that the capa- 

 city, or what has been called the specific heat of the scales, was 

 the same as that of an equal weight of solid iron, he arrived at 

 the conclusion, that heat is not a material substance, but the 

 mere effect of motion. (Philosophical Transactions, 1798.) But 

 it will be shown hereafter, that what is called capacity or specific 

 heat, is not a measure of the quantity in different bodies ; and 

 that this mode of estimating their latent or combined caloric is 

 fallacious. 



