INQUIRIES 



CONCERNING 



THE MODE OF THE PROPAGATION OF HEAT IN 



LIQUIDS. 



THE motions in fluids which result from a change 

 in their temperature give rise to so great a number 

 of phenomena, that philosophers cannot bestow too 

 much pains in investigating that interesting branch of 

 knowledge. 



When heat is propagated in solid bodies, it passes 

 from particle to particle, de proche en proche, and appar- 

 ently with the same celerity in every direction ; but it 

 is certain that heat is not transmitted in the same manner 

 in fluids. 



When a solid body is heated and plunged in a cold 

 liquid, the particles of the liquid in contact with the 

 body, being rarefied by the heat that they receive from 

 it, and being rendered specifically lighter than the sur- 

 rounding particles, are forced to give place to these last 

 and to rise to the surface of the liquid ; and the cold par- 

 ticles that replace them at the surface of the hot body, 

 being in their turn heated, rarefied, and forced up, all 

 the particles thus heated by a successive contact with 

 the hot body form a continued ascending current, 

 which carries the whole of the heat immediately towards 

 the surface of the liquid, so that the strata of the liquid 

 situated at a small distance under the hot body are not 

 sensibly heated by it. 



