370 
PROFESSOR GRAHAM ON THE MOTION OF GASES. 
The conclusion suggested by this result, that the transpiration time of ammonia is 
one-half that of oxygen, is not supported so strongly by capillary tubes of great 
resistance. 
(2.) Experiments were made with capillary M, 52-5 inches in length ; thermometer 
61°, barometer 29*900 to 29*908 inches. The time of air being 1110, 1111, and 1111 
seconds, that of ammonia was 632, 632, and 632 seconds; as 1 to 0*5688. Referred 
to oxygen, the result becomes — 
Transpiration time of ammonia 0*5119 
A second series of experiments with the same capillary, thermometer 61°*5 and 
barometer 29*800 to 29*810, gave a very similar result, namely, 1121 and 1123 seconds 
for air, and 640 and 640 seconds for ammonia; numbers which are as 1 to 0*5704, 
and give, — 
Transpiration time of ammonia 0*5134 
(3.) A third series of experiments was made upon this gas under pressure in the 
globular digester, and escaping into air by the sheaf of thirty capillary tubes P. The 
thermometer was at 60°, and the barometer from 29*888 to 29*918 inches during the 
experiments. 
Table XIII. — Transpiration of Ammonia (into air). 
Height of gauge barometer 
above 1 atmosphere. 
Air. 
Ammonia. 
Experiment I. 
Experiment II. 
Experiment I. 
Experiment II. 
inches. 
// 
// 
20 
0 
0 
0 
0 
15 
218 
217 
124 
124 
10 
319 
321 
182 
182 
8 
186 
186 
107 
106 
6 
243 
243 
138 
139 
4 
354 
355 
201 
201 
2 
621 
621 
350 
357 
1 
635 
645 
352 
350 
From 20 inches to 1 
2576 
2588 
1454 
1459 
The observation at 1 inch, or even at 2 inches, does not admit of the same precision 
as in the higher parts of the scale, owing to the slowness with which the mercury 
descends, leaving a doubtful period of 3 or 4 seconds which the mercury is in passing 
the mark. The experiments at different parts of the scale, it will be seen, concur in 
giving nearly the same result, except for the last inch, where this uncertainty appears 
to have occasioned a sensible error. 
Transpiration times of Ammonia at different pressures. 
Air =1. 
Oxygen =1. 
From 20 to 10 inches ... 
From 10 to 6 inches ... 
From 6 to 2 inches ... 
From 2 to 1 inch 
0-5693 
0-5711 
0-5684 
0-5484 
0-5112 
0-5128 
0-5104 
0-4936 
