. 
Veight afcribed to Hea. 194 
Tt is, no doubt, upon the fuppofition that heat is.a fub- 
ftance diftinét from the heated body, and which is accumu, 
lated in it, that all the experiments which have been under. 
taken with a view to determine the weight which bodies have 
been fuppofed to gain, or to lofe, upon being heated or cooled, 
have been made; and upon this fuppofition (but without, 
however, adopting it entirely, as I do not conceive it to be 
fufficiently proved,) all my refearches have been direéted. 
The experiments with water, and with ice, were made in 
a manner which I take to be perfectly unexceptionable; in 
which no foreign caufe whatever could affect the refults of 
them; and the quantity of heat which water is known to 
part with, upon being frozen, is fo confiderable, that if this 
lofs has no effect upon its apparent weight, it may be pre- 
fumed that we {hall never be able to contrive an experiment 
by which we can render the weight of heat fenfible. 
Water, upon being frozen, has been found to lofe a quan- 
tity of heat amounting to 140 degrees of Fahrenheit’s ther- 
ynometer; or, which is the fame thing, the heat which a 
given quantity of water, previoufly cooled to the temperature 
of freezing, actually lofes, upon being changed to ice, if it 
were to be imbibed and retained by an equal quantity of 
water, at the given temperature, (that of freezing,) would 
heat it 140 degrees, or would raife it to the temperature of 
(32° + 140) 162° of Fahrenheit’s thermometer, which is 
only 60° fhort of that of boiling water; confequently, any 
given quantity of water, at the temperature of freezing, upon 
being actually frozen, lofes almoft as much heat as, added 
to it, would be fufficient to make it boil. 
It is clear, therefore, that the difference in the quantities 
of heat contained by the water in its fluid ftate, and heated 
to the temperature of 61° F., and by the ice, in the experi- 
ments before-mentioned, was a¢ Jea/? nearly equal to that 
between water in a {tate of boiling, and the fame at the tem- 
perature of freezing. 
But this quantity of heat will appear much more confider- 
able, when we confider the great capacity of water to confain 
heat, and the great apparent effect which the heat that water 
ees upon being ‘frozen would produce, were it to be im- 
bibed 
