THE THERMAL EFFECTS OF FLUIDS IN MOTION. 
581 
in diameter, and then enters the coil of pipes in the bath D. Thence, after issuing 
from the porous plug, it passes through the gasometer E, and ultimately arrives again 
at the pump C. This complete circulation is of great importance, inasmuch as it permits 
the gas Tvhich has been collected in the meter to be used for a much longer period than 
would otherwise have been possible. A glass vessel full of chloride of calcium is placed 
in the circuit at F, and chloride of calcium is also placed in the pipe at f. A small 
tube leading from the coil is carried to the shorter leg of - the glass siphon gauge G, of 
which the longer leg is 17 feet, and the shorter 12 feet long. 
The thermometers employed were all carefully calibrated, and had about ten divisions 
to the degree Centigrade. We took the precaution of verifying the air- and bath-ther- 
mometers from time to time, especially when high temperatures were used, in which 
latter case a comparison between the thermometers at high temperature was made 
immediately after each experiment. 
Atmospheric Air. 
In the experiments described in the present paper, the air was not deprived of its 
carbonic acid. It was simply dried by transmitting it in the first place, before it entered 
the pump, through a cylinder 18 inches long and 12 inches in diameter filled with 
chloride of calcium, and afterwards, in its compressed state, through a pipe 12 feet long 
and 2 inches in diameter filled with the same substance. The experiments were princi- 
pally carried on in the winter season ; so that the chloride kept dry for a long time. 
From its condition after some weeks’ use, it was evident that the water was removed, 
almost as much as chloride of calcium can remove it, after the air had traversed three 
inches of the chloride contained by the first vessel. 
Table I. 
No, of experiment. 
Cubical inches of 
air transmitted 
per minute. 
Pressure over that 
of the atmosphere, 
in inches of mercury. 
Temperature of 
the bath. 
Thermal efifect. 
Correction on 
account of conduction 
of heat. 
Corrected thermal 
effect. 
[ Thermal effect re- 
duced to the pres- 
sure of 100 inches 
of mercury.; 
Time occupied 
by experiment, 
in minutes. 
Number of observa- 
tions comprised in 
each mean. 
Extreme range 
of the temperature 
of the bath. 
Extreme range 
of the temperature 
of the air. 
Extreme range 
of the pressure. 
1 
3000 
83-96 
4-499 
-0-711 
-0-044 
-0-755 
-6-900 
14 
5 
0-020 
6-015 
2-25 
2 
3600 
13619 
6-112 
-1-11 
-0-058 
-1-168 
-0-858 
24 
7 
0-017 
0-055 
1-7 
3 
2600 
156-59 
6082 
-1-307 
-0-094 
-1-401 
-0895 
15 
5 
0-009 
0-065 
8-0 
4 
1750 
139-58 
7-471 
-1-137 
-0-122 
- 1-259 
-0-902 
24 
15 
0-006 
0-19 
5-3 
5 
2250 
153-9 
7-640 
-1-231 
-0-103 
-1-334 
-0-867 
12-5 
10 
0-008 
0-028 
3-6 
6 
2300 
159-3 i 
8-546 
-1-252 
-0-102 
-1-354 
-0-850 
18 
20 
0-017 
0-105 
3-0 
7 
2060 
165-73 
8-2 
-1-329 
-0-121 
-1-450 
-0-875 
14 
15 
0-034 
0-128 
4-8 
8 
1500 
129-73 
8-72 
-1-019 
-0-127 
-1-146 
-0-883 
8 
9 
0-008 
0-135 
2-9 
9 
5000 
128-9* 
24-92 
-0-983 
-0-037 
-1-020 
-0-791 
12 
8 
0-015 
0-09 
7-0 
10 
4600 
122-8 
27-81 
-0-874 
-0-036 
-0-910 
-0-741 
26 
15 
0-029 
0-064 
0 
11 
5000 
123-5 
42-64 
-0-947 
-0-036 
-0-983 
-0-796 
8 
4 
0-127 
0-122 
7-0 
12 
4800 
137 
43-54 
-0-943 
-0 037 
-0-980 
-0-715 
6 
3 
0-02 
0-02 
0 
13 
5000 
127-5 
47-92 
-0-937 
-0-037 
-0-974 
-0-764 
6 
4 
0-058 
0-09 
2-0 
14 
3700 
147 
49-96 
-0-969 
-0-049 
-1-018 
-0-692 
35 
30 
0-14 
0-26 
0 
15 
5600 
146 
53-375 
-0-860 
-0-028 
-0-888 
-0-608 
28 
30 
0-05 
0-08 
0 
16 
5700 
146 
64-9 
-0-870 
-0-029 
-0-899 
-0-616 
24 
20 
0-18 
0-23 
0 
17 
2700 
112-43 
89-901 
-0-469 
-0-033 
-0-502 
-0-446 
20 
10 
0-112 
0-23 
8-6 
18 
1700 
147 
90-353 
-0-821 
-0-091 
-0-912 
-0-620 
4 
3 
0-022 
0-085 
0 
19 
1700 
153-16 
92-486 
-0-756 
-0-083 
-0-838 
-0-547 
19 
10 
0-202^ 
0-273 
7-0 
20 
156-5 
92-603 
-0-674 
-0-040 
-0-714 
-0-456 
12 
10 
0078 
0-19 
3-5 
21 
3800 
146 
93-78 
-0-700 
-0-036 
-0-736 
-0-504 
24 
20 
0-236 
0-255 
0 
22 
4600 
158-5 
97-528 
-0-722 
-0-029 
-0-751 
-0-474 
20 
16 
0-112 
0115 
0 
4 5 6 7 8 9 10 11 12 13 
4 ir 9. 
