JQg •N FLUIDS AS CONDVCTORS OF HEAT. 



XII. 



Obfervalions vpon the Do6irine of Count Ruwford rejpe^ing the 

 want of direct condudii/ig Poicer in Fluids with regard to 

 Meat, By Cix. Berthollet. 



(Concluded from page 140.^ 



Nicliolfofl, 1 AM of opinion, that the experiments of Nicholfon, of 



Tbompion and xhompfon, and of Murray, leave no doubt on the com- 



Murray have ... 



proved, that heat munication oF heat between the particles of liquids : fome of 

 pades through them flu)w that the motions of the folid corpulcules which 



tht particles of . .- • i r -n i • i r o 



riuiirj that cur- are agitated in a liquid, may often nuflead, with relpeci to 

 rt .Its are often j^g currents which are believed to be perceptible : but theic 

 thar fiuids'd ffer exiftence muft not, for this reafon, be denied, when a dif- 

 in conduding ference between the fpecific gravities is fuddenly eftabliihed, 

 ^°^"* and when the' heat is communicated at the lower part of a 



veflel. The others prove that the communication of heat 

 may be made through a liquid in which no current can be 

 fuppofed to tranfport it immediately lo a folid body, and they 

 prove that hquids are polTefTed of a condu(5iing faculty which 

 differs in its intenfity ; but it is not to be interred from this, 

 that the locomotion of the particles of liquids does not con- 

 tribute to eftablifli an equilibrium of temperature more fpeedily : 

 it is even probable, that the latter effefl is generally the 

 greateft. 

 Thefe general The foregoing ccnfiderations, into which I have admitted 



fa<fts account for the application of the faculty of communicating heat common 

 noinena. ^^ ?" bodies, of the conduding Oiflerence, and of the more 



fpeedy Ciillribution ot heai by means of the difference of the 

 fpecific gravity which it introduces between the panicles of a 

 fluid, feem to me to account for all the plienomena which the 

 difcernmenl ot Rumfbrd has made public. 

 Thatgafesrc- Thele conhderations lead me loan opinion very different 



ccive heat very from his ; it is known wiih v%hat rapidity the thermolcopes, 



rapidly, is feen . . ' •' , r > 



in the expanfion or air 'hermometers, indicate the variations of temperature : 



of airther- Piglet could not obferve a fecond of difference between the 



mom' 'crs and , .1 r 1 • / i 



airballoofl3. elevation of a thermometer of this delcriptiorl, and tne 



emanation of radiant heat by a body placed at a diflance: it 

 has been oblerved, that aerollals experience a ludden dilata- 

 tion 



