the Weight ascribed to Heat. n 



To remedy these evils, and also to render the experi- 

 ment more striking and satisfactory in other respects, I 

 proceeded in the following manner : 



Having provided three bottles, A, B, and C, as 

 nearly alike as possible, and resembling in all respects 

 those already described, into the first, A, I put 4214.28 

 grains of water, and a small thermometer, made on 

 purpose for the experiment, and suspended in the bot- 

 tle in such a manner that its bulb remained in the mid- 

 dle of the mass of water; into the second bottle, B, I 

 put a like weight of spirit of wine, with a like thermom- 

 eter ; and, into the bottle C, I put an equal weight of 

 mercury. 



These bottles, being all hermetically sealed, were 

 placed in a large room, in a corner far removed from 

 the doors and windows, and where the air appeared 

 to be perfectly quiet ; and, being suffered to remain 

 in this situation more than twenty-four hours, the heat 

 of the room (61) being kept up all that time with as 

 little variation as possible, and the contents of the bot- 

 tles A and B appearing, by their inclosed thermometers, 

 to be exactly at the same temperature, the bottles were 

 all wiped with a very clean, dry, cambric handkerchief; 

 and, being afterwards suffered to remain exposed to the 

 free air of the room a couple of hours longer, in order 

 that any inequalities in the quantities of heat, or of 

 the moisture attached to their surfaces, which might 

 have been occasioned by the wiping, might be corrected 

 by the operation of the atmosphere by which they were 

 surrounded, they were all weighed, and were brought in- 

 to the most exact equilibrium with each other, by means 

 of small pieces of very fine silver wire, attached to the 

 necks of those of the bottles which were the lightest. 



