78
THE NATURE AND
[sect. II.
lowing table, they serve here to indicate that the observed numbers are probably
too low for the true ones. 1
111. Experiments on the Force of the Vapour of Sulphuret of Carbon,
by M. Cagniard de la Tour.
Volume in liquid state 8 parts.
Volume in the state of vapour 20 parts.
Degrees of heat by
Force.
Difference.
Force of vapour by
Fahrenheit.
formula below.
Atmospheres.
Atmospheres.
Atmospheres.
212°
4-2
4-03
2345
5-5
1-3
5-3
257
7-9
2-4
6-8
279-5
10-0
2-1
8-7
302
130
30
11-0
324-5
16-5
3-5
13-8
347
20 2
37
17-3
369-5
24-2
40
21-3
392
28-8
4-6
26-2
414-5
33-6
4-8
31-9
447
40-2
6-6
42-0
469-5
47-5
7-3
503
492
57-2
9-7
60-2
514-5
66-5 r _ f . .
_ Lvapour.
89-2 1
9-3
71-4
537
11-3
84-5
559-5
11-4
99-5
572
98-9
9-7
594-5
1143
15-4
617
1296
15-3
628-25
133-5
3-9
The irregularities in all M. Cagniard de la Tour’s experiments would be in part
occasioned by the expansion of the tubes under such high pressures and tem
peratures ; hence, to attempt a minute comparison would only show a want of
attention to physical effects too common in such inquiries. The usual practice of
attempting to supply want of observation by minute calculations, is one of the
great defects of the present mode of scientific inquiry, as applied to improve the
scientific arts.
112. The forces of various other substances have been tried, but not with
much attention to the selection of such as are adapted for the acting vapours in an
engine ; as, for that purpose, one should be chosen which affords the highest power
1 The rule in logarithms for sulphuret of carbon, by which the calculated numbers in these
tables were found, is
log. /=6 ^log. (t + 280) — 2-34488^)
to the point where the liquid becomes wholly vapour.