PROFESSOR GRAHAM ON THE MOTION OF GASES. 
1370 seconds, the time at 50°, the time at 203° is 1780-9 seconds ; the time actually 
observed was 1792-5 or 11-6 seconds more, a close approximation considering the 
difficulties of the experiment. 
But the resistance does not require to be so excessive as in capillary V to bring 
out the law of temperature. It appeared equally distinct in a capillary tube, having 
only one-ninth of the resistance of V for equal lengths. This tube however was 
used in lengths of 4^ inches (instead of 3 inches), so that its resistance is properly 
stated at one-sixth of V. A sheaf was put together of thirty lengths of the new tube, 
forming the compound capillary Q. The digester was employed of its full capa- 
city, of 72 cubic inches, to contain the compressed air, which was allowed to escape 
by the channels of Q into the atmosphere. The range of pressure was from 20 inches 
to 8. The observed times at 49° and 203° without reduction were 802, 799 and 798 
seconds at the low temperature, and 1350 and 1347 seconds at the high temperature. 
Taking the means 800 and 1349 seconds and reducing as in the experiments with V, 
we have 1036-1 seconds for the high temperature. Now the calculated time for that 
temperature is 104T6 seconds, or only 5*5 seconds above the observed time. The 
barometer during these experiments marked from 30-044 to 30-058 inches. 
In another series of experiments, the time observed at 49° being 797 seconds, the 
times observed after reduction, at certain intermediate temperatures, were as 
follows : — 
Table XVI. — Times of transpiration of Air (into air) in seconds. 
Temperature. 
Observed time. 
Calculated time. 
Error of observation. 
49 Fahr. 
797 
797 
96 
879-3 
870-4 
+ 8-9 
141 
950-1 
935-8 
+ 14-3 
203 
1020-8 
1032-1 
-11-3 
The deviations of the observed from the calculated times, from 8-9 to 14-3 seconds, 
are small considering the difficulty of maintaining the temperature constant in the 
experiments. Nor are they always in the same direction. This appears in a third 
series of experiments, conducted in the same manner as the last, of which I subjoin 
the results. 
Table XVII. — Times of transpiration of Air (into air) in seconds. 
Temperature. 
Observed time. 
Calculated time. 
Error of observation. 
49 Fahr. 
797 
797 
96 
897-3 
870-4 
+ 8-9 
141 
932-3 
940-8 
-8-5 
These observations leave little doubt that the transpiration of air at different tem- 
peratures takes place according to the law by which the times above have been cal- 
3 £ 
MDCCCXLIX. 
