42 
Proceedings of the Royal Society 
XXV. Mixture of Air and Olefiant Gas, containing *032 yer cent. 
Jyy volume of Olefiant Gas. — The absorber, filled with the dry air of 
Experiment XXIV., was surrounded by water at 12°‘6 C. When 
a constant pressure of 9338*5 had been attained, dry olefiant gas 
was driven into the vessel, raising the pressure to 9341*5. Hence 
the mixture contained *032 per cent, by volume of olefiant gas. 
Time. 
Pressure. 
Time. 
Pressure. 
m. 
s. 
m. 
s. 
0 
0 
9340*9 
5 
30 
9374*0 
0 
17 
9339*9 
6 
13 
9379*1 
0 
26 
9338*9 
6 
52 
9384*1 
0 
54 
9336*9 
7 
15 
/ 
Steam issuing 
1 
14 
9338*9 
1 
freely. 
2 
0 
9343*9 
7 
50 
9394*1 
2 
38 
9349*0 
8 
24 
9399*1 
3 
10 
9354*0 
10 
15 
9404*1 
3 
41 
9359*0 
12 
20 
9405*0 
4 
13 
9364*0 
13 
50 
9406*0 
4 
53 
9369*0 
19 
10 
9406*4 
XXVI. — Damp Air, containing per cent, hy volume of. Water 
Vapour. — A current of the damp air of the laboratory was drawn 
through the absorber, which contained initially the gas in Experi- 
ment XXV., until, as determined by calculation, it contained a 
quantity of olefiant gas so small as to be negligible. The quantity 
of water vapour present in the damp air, with which the reservoir 
was then filled, was found by determining the dew-point. The 
room in which the experiments were carried out was large, and 
there was a slow passage of air through it. The dew-point was 
determined by observation of wet and dry bulb thermometers. The 
temperatures they indicated were respectively 15° and 12° *8 C. 
The barometric pressure (reduced to 0° C.) was 759*83 mm. The 
pressure of the water vapour was therefore 9*71 mm., and the damp 
air contained consequently 1*278 (or about 1*3) per cent, by volume 
of water vapour. 
Time. 
Pressure. 
Time. 
Pressure. 
. m. s. 
m. s. 
0 0 
9331*6 
0 55 
9329*1 
0 25 
9330*1 
1 17 
‘9330*0 
