354 CONTRACTION OP WATER BY HEAT. 



and lighter particles from the others, ought, I conceive, to 

 have taken place. The temperature of the top, however, 

 never indicated the arrival of warmer particles. It never af- 

 cended above the point of equilibrium. 



From thefe experiments I concluded, that the uniformity 

 of temperature was eftablifhed by an actual communication 

 and interchange of heat between the particles. 

 Count Rumford It may not, however, be improper to ftate, that Count 

 the mixture 3 Runiford, with whom feveral years ago I had the pleafure 

 might be too of converting upon this fubject, alledged, that the inter- 

 lowoff t0al " mixture n) 'ght, be fo complete as to prevent any feparation 

 tie-n : whatever. 



If it be a property cflential to fluidity, that heat cannot pafs 

 from one particle to another, the particles of different fluids 

 ought to be equally incapable of imparting caloric mutually to 

 each other. Unfortunately, however, for the fpeculation, the 

 the caloric is fo communicated Though, a priori, I enter- 

 tained no doubts refpecling the refult of the experiment, I 

 but oil and ^ poured a quantity of olive oil which had been heated by im- 

 thecom°mon Uir me,, fion in a veflei of boiling water for half an hour, upon an 

 temperature by equal volume of water of 38°, and agitated the mixture, by 

 MhiSrthefanie ^ ia ^ m g f° r a quarter of a minute. The common temperature 

 when feparate. produced was 78°, and the heat had gone from the oil into the 

 the water ; for when the fluids feparated, and had arranged 

 themfelves according to their fpecific gravity, both of them had 

 the fame temperature of 7S° *. 



The experiments of the two defcriptions now recorded, left 

 on my mind little doubt that the Count had overftrained his 

 conclusions. 

 Exp. 4. The f Zixp.jIV. I took the fame tall jar, and (lopping the tubu- 



taltjarof Exp. i ature w j t h a COIV fc j ^j e( j j t vv j tn waler f temperature 40*, 

 3, containing ... r • 



water at 40 , and placed it in a pan Alter fufpending two thermometers, 



was cooled as j n experiment firft and fecond, I poured a mixture of ice 



Tound its lower . 



'fart by ice and ant ^ fait into the pan, to the depth of 4.2 inches, the air of the 



* alt « room being 40°, as in the laft experiment. 



The tempera- Bottom. Top. Air. 



ture fell as Eleven o'clock, 40° 40° 40° 



?£&£& In 10 minutes, 3S+ 38+ 



* This is alfo very tlrikingly the cafe with mercury and 

 water.— -N. f The text is here retained. 



- In 



