332 
MR. J. P. JOULE AND PROFESSOR THOMSON ON THE 
Table X. — Experiment in which carbonic acid was forced through a plug consisting 
of 580 grs. of silk. Mean barometric pressure 29*56, equivalent to 14*452 lbs. 
Gauge under atmospheric pressure 150*8. Pump placed in connexion with the 
pipe immersed in carbonic acid at 12 h 53 m . Quantity of gas forced through the 
plug about 7170 cubic inches per minute. 
1 . 
2. 
3. 
4. 
5. 
6. 
Time of 
observa- 
tion. 
Volume per- 
centage of car- 
bonic acid. 
Pressure-gauge, and 
pressure in lbs. on the 
square inch equivalent 
thereto. 
Indication of thermometer. 
Temperature of the bath. 
Indication of thermometer. 
Temperature of the 
issuing gas. 
Cooling 
effect in 
Cent, 
degrees. 
h s 
12 42 
0 
52-2'' 
464-2 ^ 
185-6 1 
44 
0 
52-2 
lbs. 
*>52-2 =55-454 
464-35 
185-5 
46 
49 
0 
0 
52-2 
52-2 
464-4 
464-35 
>464-34= 19-072 
185-5 
185-55 
>185-53=18-323 
6-749 
50 
0 
52-2 
464-35 
185-55 
52 
0 
52-2 J 
464-4 
185-5 
54 
56-0 
464-55 
179*0 
57 
55-7 
464-65 
166-3 
1 0 
95-5n 
56-0^ 
464-3 7 
165-0 " 
5 
56-0 
464-55 
165-0 
7 
56-0 
464-5 
165-0 
9 
56-0 
464-4 
164-9 
10 
96-0 
}>94-85 
)>55-92 = 51-7 
>464-47 = 19-077 
)> 165-0 = 16*256 
2-821 
11 
55-8 
464*6 
164-9 
13 
55-6 
464-55 
164-8 
17 
56-0 
464-5 
165-0 
20 
93-03 
56-0 
464-4 J 
165-4 J 
24 
55-5^| 
464-6 
166-0 
25 
55-7 
464-6 
166-3 
27 
56-1 
464-6 
166-8 
30 
85-92 
56-0 
^55*94=51-68 
464-7 
^464*71 = 19*088 
167-9 
>167*8=16*538 
2-550 
35 
56-1 
464-8 
168-9 
36 
56-1 
464-8 
169-1 
38 
56-1 J 
464-9 J 
169-6 J 
In the above experiment, as well as in those of the adjoining Tables, the sudden 
diminution of pressure on connecting the pump with the receiver containing carbonic 
acid, is in perfect accordance with the discovery by Professor Graham of the superior 
facility with which that gas may be transmitted through a porous body compared 
with an equal volume of atmospheric air. 
