of Porcelain, Gilded and not Gilded. 247 



before this illustrious Assembly, it might be said that in 

 the case in question the exterior surfaces (the one of 

 white porcelain, the other of gold) of the two vessels 

 being intimately exposed to the violent action of a rapid 

 succession of the very cold particles of the surrounding 

 fluid, became, both of them, cooled to such an extent 

 that they were reduced to about the same temperature 

 in spite of the continual heating action of the walls of 

 the vessels in contact with them on the opposite side ; 

 and that, as a consequence, since these surfaces exercised 

 on the walls of the vessels which they covered cooling 

 actions which were sensibly equal, the two vessels were 

 of necessity cooled with the same rapidity. 



I will conclude this memoir with some observations 

 which may serve to throw light on a point in the theory 

 of heat which is of very great importance. 



The great rapidity with which heat is communicated 

 from one body to another, when two bodies of different 

 temperatures are in contact, compared with the slowness 

 of communication which takes place when the bodies 

 are separated, however little, one from the other, has 

 had a considerable tendency to give authority to the opin- 

 ion quite generally adopted by chemists, that there are 

 two modes by which heat can be transmitted from one 

 body to another ; that is, at a distance, by radiant 

 caloric^ and, on contact, by an actual transfusion of the 

 same substance. If, however, attention be paid to a 

 fact which no one up to this time has called into ques- 

 tion, the phenomenon under consideration can, as it 

 seems to me, be explained in a perfectly clear and satis- 

 factory manner, without having recourse to such an 

 extraordinary supposition as that there are two different 

 modes by which heat is communicated. 



