SECT. II.]
PROPERTIES OF STEAM.
75
Bettancourt’s boiling point is not stated, but appears to have been at 173°, 1 and
his results like Dr. Robison’s are too small at low temperatures.
Dr. Ure’s experiments are confirmed by those of Mr. Dalton, and may be relied
on as approaching very near the truth. The formula, it will be observed, repre
sents them with considerable accuracy.
Of the Elastic Force of the Vapour of Sulphuric Ether.
106. M. Cagniard de la Tour made several experiments on ether in the
same manner as those on alcohol, art. 104. The ether was converted into vapour
in a space less than twice its original volume by a temperature of 392°. This
experiment was thrice repeated, with the same result, and 528 parts of air were
compressed to 14, giving an elastic force of 37*7 atmospheres. 2 * * *
107. Other trials were made, the results of which are shown in the following
table.
M. Cagniard de la Tour’s Experiments on Ether.
Volume in the liquid state 7 parts.
Volume in the liquid state 3J parts.
Volume in the state of vapour
Volume in the state of vapour
20 parts.
20 parts.
Force as ex-
Force of va-
Temperature
Force of vapour
Differences.
panding gas in
Force of vapour
Differences.
pour in atmo-
by Fahrenheit.
in atmospheres.
atmospheres, by
in atmospheres.
spheres, by for-
formula below.
mula below.
212°
5-6
5-78
234-5
7-9
2-3
7-9
257
10-6
2-7
14-0
1063
279-5
12-9
2-3
17-5
3-5
14-1
302
18-0
5-1
22-5
5-0
18-4
324-5
22-2
4-2
28-5
6-0
23-8
347
369-5
392
28-3 cf f ,
ni» py f fetate of
vapour.
48-5
6-1
9-2
11-0
/ State of
\ yapour.
50-5
6- 5
7- 0
8- 5
30-6
38-7
48-0
414-5
59-7
11-2
58-0
7-5
60-7
447
68-8
9-1
68-8
63-5
5-5
82-3
469-5
78-0
9-2
70-5
66-0
2-5
100-7
492
86-3
8-3
72-2
70-5
4-5
514-5
92-3
6-0
73-9
74-0
3-5
537
104-1
11-8
75-6
78-0
4-0
559-5
112-7
8-6
77-4
81-0
3-0
572
119-4
6-7
78-3
85-0
4-0
594-5
123-7
4-3
80-0
89-0
4-0
617
130-9
7-2
81-8
94-0
5-0
1 Prony’s Architecture Hydraulique, vol. ii. p. 180.
2 The experiments on sulphuric ether may be very nearly represented by the formula,
/ = C i^ 8 ^ Q )i or lo S*/ = 6 0°g- R + 21 °) - 2-25212)
when the ether boils at 104° or 105°; but for ether boiling at 98°, the constant logarithm should
be 2-23953.
In the above experiment the formula for ether boiling at 105° gives 48 atmospheres for its elastic
force at 392°; but the correspondence with the tabular experiments is nearer.