190 Count Rumford’s Inquiry concerning 
now approached it very gently, and caused it to vibrate ; and I 
had the satisfaction to find, — not only that it moved with the 
utmost freedom, — but also, — when its vibration ceased, — that it 
rested precisely at the point from which it had set out. 
I now removed the bottle B from the balance, and put the 
bottle C in its place; and I found that that likewise remained 
of the same apparent weight as at the beginning of the experi- 
ment, being in the same perfect equilibrium with the bottle A 
as at first. 
I afterwards removed the whole apparatus into a warm room, 
and, causing the ice in the bottle A to thaw, and suffering the 
three bottles to remain till they and their contents had acquired 
the exact temperature of the surrounding air, I wiped them 
very clean, and, comparing them together, I found their weights 
remained unaltered. 
This experiment I afterwards repeated several times, and 
always with precisely the same result ; the water, in no instance , 
appearing to gain, or to lose, the least weight, upon being 
frozen, or upon being thawed ; neither were the relative weights 
of the fluids in either of the other bottles in the least changed, 
by the various degrees of heat, and of cold, to which they were 
exposed. 
If the bottles were weighed at a time when their contents 
were not precisely of the same temperature , they would fre- 
quently appear to have gained, or to have lost, something of 
their weights ; — but this doubtless arose from the vertical cur- 
rents which they caused in the atmosphere, upon being heated 
or cooled in it ; or to unequal quantities of moisture attached 
to the surfaces of the bottles ; — or to both these causes operating 
together. 
