PASSAGE OF HEAT THTiOX/GH FLUIDS, 361 



The thermometer, whose bulb was in the woodon cup, re- 

 itiained at perfect rest from the beginning of the experiment to 

 the end of it, without shewing the shghtest sign of being in. 

 any Way affected by the hot water which was so near it. 



These experiments were made at Munich, in the month of ' 



July 1805, the temperature of the air and of the water con- 

 tained in the vessel, KL, being 70° Farenh. 



A small thermometer, placed in the water, contained in the 

 annular vessel, H I, in such a manner that its bulb was scarce- 

 ly submerged, marked that this water had received a little 

 heat in each of the three experiments. 



Another similar thermometer, placed in the water contain- 

 ed in the large vessel, KL, immediately under its surface and 

 near one side of the vessel, shewed that this water had not ac- 

 quired any sensible increase of temperature during the experi- 

 ments. 



From the results of these experiments we are authorized to The expert- 



conclude, that heat does not descend in water to a sensible P^^*,^^'^^^*''^* 



heat does not 

 distance, in cases where the particles of the liquid which re- pass down- 



ceive heat are eN posed to be displaced and forced upwards by ^^^ds m fluids 



*^ » . . "^^ "-^ circtt- 



the surrounding colder and denser particles ; that is to say, in late. 



all the cases (and they are the most common) where heat is 



applied to the strata of the liquid situated under its surface. 



But the results of the experiments in question do not prove Bnt they do not 

 that heat cannot in'any case descend in water; and still less S^°j^ „ ^ |. 

 can it be inferred from them, that all direct communication of conduct direct- 

 heat, in this liquid, from particle to particle, de procke en '^' 

 vroche, is impossible. They do not even prove that heat did not 

 descend, to a small distance, below the level of the end of the 

 wooden tube, in these experiments ; for it is certain that that 

 event could take place without the thermometer, which was 

 situated a little lower, being in any way affected by that heat. 



The particles of water, situated at a very small distance The fluid above 



below the level of the lower end of the wooden tube, beino ]^^ thermome- 



•- ter was not 

 heated by the stratum of hot water which rested immediately quiescent. 



on them, might have been displaced by the surroundmg colder 

 and denser particles, and forced to rise to the surfece; and 

 these last being in their turn heated, forced upwards and re- 

 placed by other cold particles, it is evident that the heat could 

 not make its way downwards so far as to arrive at the thermo- 

 VoL, XIV,— September, 1806. Aaa meter 



