14:0 , ON FLVIDS AS CONDVCTORS OF HEAT. 



ration without producing the mixture of the two fluids, fo that 

 their various motions were not the effed of a current which 

 carried them with it, and neverthelefs, the heat was communi- 

 cated to all the liquid. The propo/gation of the heat, and the 

 agitation of corpufciiles, which have nearly the fame fpecific 

 gravity, may therefore take place, independently of the circu- 

 latory motion, which is only elkblirtied when there is a differ- 

 ence of temperature of a certain intenfity between the differ- 

 ent ftrata of a fluid. 

 Murray made Murray has oppofed Rumford's opinion with experiments 



experiments in fiill more diredt, and not lefs conclufive; * he placed the bulb 

 comainingr* ^^ a thermometer in a cylinder of ice, which he filled alter- 

 flnid. The heat nately with oil and mercury; he afterwards brought a heated 

 wS '^'*'^"' ^^^y "^^"^ ^^^ furnace of the liquid; the thermometer rofe fe- 

 veral degrees in both experiments; but the heat could not 

 have been conveyed by the fides of the ice whofe furface would 

 have abforbed and liquefied ; no current was eflabliftied, for 

 the moleculae of the liquid having become lighter, could not 

 take a contrary diredion, and the author avoided ufing water, 

 which contradfs on paffing from the degree of congelation to a 

 temperature a little more raifed: the heal muft therefore have 

 been communicated to the bulb of the thermometer without the 

 eftabiifliment of fuch a current as is fuppoled to be requifiie; 

 and that which ferved to dilate it was only the excefs of what 

 had liquefied part of the ice. 

 —and mercury The obfervations of Murray prove at the fame time that 

 condudted better mercury is a much more effective condudor of heat than oil 

 for the elevation of the thermometer was manifefted by its in- 

 termedium in a much (liorter time, and more ice was liquefied. 



, * Ann. de Chim. Floreal, An. X. or Philof. Journal, oaavo, I. 



165. 241. The experiments of Thcmfon and Murray, origijially 

 appeared in our Journal, and thole of Count Rumford ale alfo given, 

 for which fee the Indexes, 



(To be continued.) 



On 



