294 ^f ^^^^ Propagation of Heat 



ice. I then placed the jar in a shallow earthen dish, and 

 surrounded it to the height of the level of the top of 

 the ice with a mixture of snow and water (see Plate II.), 

 and, placing it in a room in which there had been no fire 

 made for many months, and in which the temperature of 

 the air was at 41°, I let it remain quiet two hours, in or- 

 der that the ice might acquire the temperature of 32°. 



This being done, I took the jar out of the earthen 

 dish, and, wiping the outside of it dry with a cold nap- 

 kin, I weighed the jar with the ice in it very exactly, and 

 then replaced it in the earthen dish, and surrounded it as 

 before with snow and water to the height of the level of 

 the surface of the ice. 



I then poured 73^ ounces, Troy, {^ 15,160 grains) 

 of water, at the temperature of 41°, into the jar, which 

 covered the ice to the same height to which it had been 

 covered in the former experiments, namely, to about 8 

 inches ; and suffering it to stand on the ice a certain 

 number of minutes, I then poured it off, and, wiping the 

 outside of the jar, weighed it, in order to ascertain how 

 much ice had been melted. 



In putting this cold water into the jar, the same pre- 

 cautions were used (by pouring it through the wooden 

 tube into the perforated wooden dish, &c.) as were used 

 when the experiment was made with boiling water. 



The following table shews the results of six experi- 

 ments made the same day (the 19th March, 1797), in 

 the order in which they are numbered, and which were 

 all made with the utmost care. 



