the Weight ascribed to Heat. 1B1 
with their contents, to remain in this situation till I conceived 
they must have acquired the temperature of the circumambient 
air, I wiped them afresh, with a very clean dry cambric hand- 
kerchief, and brought them into the most exact equilibrium 
possible, by attaching a small piece of very line silver wire to 
the arm of the balance to which the bottle which was the 
lightest was suspended. 
Having suffered the apparatus to remain in this situation 
about twelve hours longer, and finding no alteration in the 
relative weights of the bottles, — they continuing all this time to 
be in the most perfect equilibrium, — I now removed them into 
a large uninhabited room, fronting the north, in which the air, 
which was very quiet, was at the temperature of 29 0 , F ; the 
air without doors being at the same time at 27 0 ; and, going out 
of the room, and locking the door after me, I suffered the 
bottles to remain forty-eight hours, undisturbed, in this cold 
situation, attached to the arms of the balance as before. 
At the expiration of that time, I entered the room, — using the 
utmost caution not to disturb the balance, — when, to my great 
surprise, I found that the bottle A very sensibly preponderated. 
The water which this bottle contained was completely frozen 
into one solid body of ice ; but the spirit of wine, in the bottle 
B, showed no signs of freezing. 
I now very cautiously restored the equilibrium, by adding small 
pieces of the very fine wire of which gold lace is made, to the 
arm of the balance to which the bottle B was suspended, when 
I found that the bottle A had augmented its weight by 
part of its whole weight at the beginning of the experiment ; 
the weight of the bottle with its contents having been 4811,23 
grains Troy, (the bottle weighing 703,37 grains, and the water 
MDCCXCIX. B b 
