I6t COUNT RUMFORD's NEW EXPERIMENTS 



(ween the ordinates Kf and Bg, indicated by the refults of 

 the experiment in queftion, appears to me much too confider- 

 able to be afcribed to the imperfection of our thermometers. 

 It differs greatly To fee how far the curve P Q differs from the logarithmic, 



/cW he ^^ W6 haVC 0nIy t0 draw a lo g arithmic curvc R S thr0ll g h the 

 points g and i, and we fliall find, that the ordinates correspond- 

 ing to the points 



A, B, C, D, E. 



Infiead of being 212* 162<* 132 9 £ 10S| 32° 

 • Will be - 199.55 162 131 106f 86.35 



Difference - -2*45 -lj 0+54*35 



Afcribed to The very great difference that exifts between the temper- 



water being a ature of cold water, and that indicated by the refults of the 

 of d heat dU ° r ex P enment for tne extremity of the cylinder which was in 

 contact with this water, led me to fufpeel, that it was owing 

 to the quality poiTeffed by water in common with other fluids, 

 which renders it a very bad conductor of heat. 

 —and the cur- ^ lt ^ e true > as ^ believe I have elfewhere proved, that 

 rents in the cold.there is no fenfible communication of heat between the adja- 



Siderabl? m " Cent P articles of a fluid ' from one t0 another J and that heat is 

 propagated through fluids only in confequence of a motion of 

 their particles, refulting from a change in their fpeciiic gravity, 

 occafioned by their being heated or cooled : as the fpecific 

 gravity of water is very little altered by an inconfiderable 

 change of temperature when this fluid is near the freezing 

 point, it might have been forefeen, that a folid body a little 

 heated, and plunged into cold water, would be very flowly 

 cooled. 

 Experiment to The refult of the following experiment, which I made with 

 prove this. a v j evv to elucidate this point, will put the fact out of all doubt. 

 When the cold The three thermometers being ftationary, one, B, at 162°, 

 water was brifk- the fecond, C, at I32|°, and the third, D, at 106j°, the 

 thermometers water m contact with one of the extremities of the cylinder 

 were all greatly being ftill boiling, while the water mixed with pounded ice, 

 deprefled. which was in contact with the other extremity, was conftantly 



at the temperature of melting ice, I began to flir this mixture 

 of ice and water pretty britkly with a little flick, and I con- 

 tinued to ftir it uninterruptedly, and with the fame velocity, 

 for two and twenty minutes. 



I had fcarcely begun this operation, when I had a proof, 



that 



