326 
MR. J. P. JOULE AND PROFESSOR THOMSON ON THE 
intermediate stopcock was however partly opened, in order that by discharging a 
portion of the air before its arrival at the nozle, the pressure might not be widely 
different from that employed in the last series. In all excepting the last experiment 
recorded in the following Table, the cylinder of lime was dispensed with. 
Table II. — Experiments with a smaller quantity of air passed through a plug 
consisting of 382 grs. of cotton wool. 
1 . 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
Number of obser- 
vations from 
Cubic inches 
Water in 
Pressure in lbs. 
on the square 
inch. 
Temperature 
of the issuing 
air. 
Cooling 
which the results 
passed through 
100 grains 
Atmospheric 
Temperature of 
effect 
in Columns 
4, 6, and 7, 
are obtained. 
the nozle 
per minute. 
of air, in 
grains. 
pressure. 
the bath. 
in Cent, 
degrees. 
20 
3865 
059 
22-614 
14-513 
20-363 
20-224 
0-139 
30 
3960 
0-73 
22-818 
14-514 
19-853 
19-769 
0-084 
20 
Not observed. 
0-56 
22-818 
14-604 
20-481 
20-407 
0-074 
45 
3125 
0-65 
22-296 
14-590 
20-584 
20-313 
0-271 
20 
Not observed. 
1-23 
23-000 
14-518 
18-636 
18-476 
0-160 
36 
Not observed. 
1-20 
22-616 
14-520 
20-474 
20-336 
0-138 
50 
Not observed. 
1-36 
22-582 
14-518 
20-485 
20-325 
0-160 
Mean 
0-90 
22-678 
14-540 
20-125 
19-979 
0-146 
Table III. — Experiments in which the entire quantity of air propelled by the pump 
was passed through a plug consisting of 382 grains of cotton wool. The cylinder 
of lime was not employed. 
1 . 
2. 
3. 
4. 
5. 
6. 
7- 
8. 
Number of obser- 
vations from 
which the results 
in Columns 
4, C, and 7, 
are obtained. 
Cubic inches 
passed through 
the nozle 
per minute. 
Water in 
100 grains 
of air, in 
grains. 
Pressure in lbs. 
on the square 
inch. 
x\tmospheric 
pressure. 
Temperature of 
the bath. 
Temperature 
of the issuing 
air. 
Cooling 
effect 
in Cent, 
degrees. 
7 
11766 
0-56 
36-625 
14-583 
19-869 
19-535 
0 
0-334 
10 
Not observed. 
0-56 
35-671 
14-790 
20-419 
20-098 
0-321 
10 
Not observed. 
0-36 
35-772 
14-504 
16-096 
15-730 
0-366 
10 
Not observed. 
0-36 
35-872 
14-504 
16-104 
15-721 
0-383 
10 
Not observed. 
0-36 
36-026 
14-504 
16-232 
15-869 
0-363 
Mean 
0-44 
35-993 
14-577 
17*744 
17-390 
0-354 
In the next series of experiments the air was passed through a plug of silk, formed 
by rolling a silk handkerchief into a cylindrical shape, and then screwing it into the 
nozle. The silk weighed 580 grains, and the small quantity of cotton wool placed 
on the side next the thermometer in order to equalize the stream of air more com- 
pletely, weighed 15 grains. The stopcock was partly opened as in the experiments 
of Table II., in order to reduce the pressure to that obtained by passing the full 
