SECT. II.]
PROPERTIES OF STEAM.
53
State of the calorimeter, equal in specific heat to
42909 grains of water.
Temperature of
the room.
Temperature at
the beginning.
Temperature at
the end.
Elevation of its
temperature.
Quantity of va
pour condensed
into water.
Heat of conver
sion of the water
into vapour
in degrees.
61°
55i°
674°
12i°
Grains.
457
1029°*3
62i
57
67i
10i
377
1052-3
Mean
- 1040-81
The result of the second experiment being compared by our formula, (note to
art. 75,) we have
42909 x 10i
377
+ 67i = 1262°-5,
from whence, deducting 212° on the supposition that the specific heat of steam is
equal to that of water, we have 1050 o, 5 for the constant quantity of heat for con
version into steam. The very small difference between this and Count Rumford’s
result, arises from the fractions neglected in reducing the French to English weights.
80. Count Rumford also made experiments on the quantity of heat developed
in the condensation of the vapour of alcohol: the results of these experiments were
less regular than those of the experiments made with water, as might have been
expected, but they were nevertheless sufficiently uniform to give the quantity of
heat with considerable certainty.
The vapour which is extricated from spirit of wine, when boiled, varies a little
with the intensity of the fire used in boiling it; he took care therefore to note the
time which was taken in every experiment, in order to be able to judge, by com
paring the quantity of vapour condensed with the time employed to form it, of
the intensity of the heat employed to boil the liquid. In the following table will
be found the details and results of five experiments made on the same day,
(January 21, 1812,) with alcohol of different degrees of strength. The specific heat
of the calorimeter and the water it contained, was always equal to that of 42909
grains of water; and the thermometer employed was that of Fahrenheit.
Specific gra
vity of the
alcohol em
ployed.
Time em
ployed in the
experiment.
Temperature
of the apart
ment.
State of the calorimeter.
Quantity of
alcohol con
densed in the
calorimeter.
Heat of con
version of the
liquid into
vapour.
Temperature
at the begin
ning.
Temperature
at the end.
Elevation of
its tempera
ture.
81763
84714
85342
85342
85342
4i min.
8 —
7 —
5 —
61°
601
61
61
64
56°
55i
54i
56
57
661°
65|
68i
66i
71i
101°
10
141
10i
14i
Grains
875
755
1079
805
1102
479°-92
500-03
499-54
476 83
499-65
Mean - 49113
i Philosophical Mag. voi. xliii. p. 65.