in Fluids. 299 



The results of these experiments afford matter for 

 much curious speculation ; but I shall content myself for 

 the present with making only two or three observations re- 

 specting them. And, in the first place, it is remarkable, 

 that, although in the experiments No. 34 and No. i^St 

 of 30 minutes each, considerably less ice was melted than 

 in that No. 26, which lasted the same time, yet in that 

 No. -^^d^ of 180 minutes, more was melted than in that 

 No. 27, of the same duration. This difference in the two 

 last-mentioned experiments will be accounted for here- 

 after. 



With regard to the difference in the results of the ex- 

 periments of 30 minutes, there is no doubt but that it 

 arose from the precautions which had been taken in this 

 last set of experiments to prevent the effect of the violent 

 motions into which the hot water was thrown in being 

 poured into the jar, that less ice was melted in the ex- 

 periments No. 34 and No. i^K^ than in that No, 26. 



Secondly^ It appears that more ice was melted in the 

 same time in the experiments in which the jar was cov- 

 ered up with warm covering than in those in which it 

 was left naked and exposed to the air of the room. 



The difference is even considerable. The quantity 

 melted in 30 minutes when the jar was covered, at a 

 mean of two experiments (No. 34 and No. 35), was 690I- 

 grains ; but when the jar was naked, the quantity at a 

 mean of three experiments (No. 39, No. 40, and No. 

 41) was only 558I grains. 



Thirdly^ The quantity of ice melted under similar cir- 

 cumstances — that is to say, when the jar was naked — 

 was sensibly greater when the water was at the temperature 

 of about 41° than when it was nearly boiling hot. In 

 the experiment No. 41, when the water which was poured 



