CONTRACTION OF WATER BY HEAT. 353 



In all the experiments a thermometer bore teftimony that the In all the expe- 

 caloric defc.ended from the furface to the bottom of the fluid, ^eicended 

 and tismonftraied, at lea ft to my conviction, that fluids can 

 conduct heat. 



The progrefs of the heat, however, was very flow, and lowly. 

 atttfted the important fadt, ibr which we ought to be thank- 

 ful to the Count — That fluids are very bad conductors. 



The feeond fet of experiments was calculated to examine, 

 in a very different manner, the pofition, That all interchange 

 and communication of heat between the particles of fluids is 

 impoflible. 



When a hot and a cold fluid are mixerf together and well Other experi- 

 agitated, very foon an uniform is produced. This equality fl^ 5 ° f mUiaS 

 rauft proceed either from a communication of heat from the 

 warmer to the colder fluid, agreeably to the common opinion, 

 or from a perfect intermixture of hot and cold particles, ac- 

 cording to the notion of Count Rumford. To which caufe it 

 ought to be attributed, I conceived I might difcover, by afcer- 

 taining whether, after fuch an intermixture, any feparation of 

 the hot and cold portions took place. If the equilibrium of 

 temperature be owing to intermixture without interchange of 

 caloric, the hotter particles, as foon as the agitation ceafes, 

 ought, by reafon of their greater rarity, to accumulate, to a 

 certain degree, at the furface, and there exhibit a temperature 

 above the common one. 



I firft tried water, and mixing this fluid boiling-hot, with when hot and 

 an equal quantity nearly ice-cold, in a ftoppered glafs jar, I cold water are 

 (hook them well for a fliort time. ™^J tolZl 



I then noticed the refulting temperature, and raifmg the temperature 

 ball of the thermometer towards the furface, Ihatf an oppor* ^ g fcP^* 

 tunity of observing, that it never rofe the fmalleft portion of 

 a degree above the common temperature which had been efta- 

 bliihed. 



I next made a fimilar experiment with alcohol, fele&ing it The fame offecl 

 oh account of its remarkable disability. I fhook well, for was foum3 ivitU 

 half a minute, a mixture of equal parts of alcohol at tempe- 

 40° and at temperature 170°. ^The refulting temperature of 

 the mafs was H0°, 



Now, if this was a mixture of particles at 40° and at 170°, 

 as the difference of fpecific gravity between the fluid at thefe 

 temperatures is very confiderable, fome feparation of the warmer 



Vol, XII.*-Svpplement, A a and 



