iS8 Count Rumford’s Inquiry concerning 
heat; or, in other words, — the degrees of facility or difficulty 
with which they acquire the temperature of the medium in which 
they are exposed ; — or the time taken up in that operation ; 
and, consequently, was not absolutely certain as to the equality 
of the temperatures of the contents of the bottles at the time 
when their weights were compared, I determined now to repeat 
the experiments, with such variations as should put the matter 
in question out of all doubt. 
I was the more anxious to assure myself of the real tempera- 
tures of the bottles and of their contents, as any difference in 
their temperatures might vitiate the experiment, not only by 
causing unequal currents in the air, but also, by causing, at 
the same time, a greater or less quantity of moisture to remain 
attached to the glass. 
To remedy these evils, and also to render the experiment 
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 sus- 
pended in the bottle in such a manner that its bulb remained in 
the middle of the mass of water ; into the second bottle, B, I put 
a like weight of spirit of wine, with a like thermometer ; 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 win- 
dows, and where the air appeared to be perfectly quiet; and, be- 
ing suffered to remain in this situation more than twenty-four 
hours, the heat of the room (6i°) being kept up all that time 
