208 
PROFESSOR TYNDALL ON THE ABSORPTION AND 
Table VII. — Carbonic Acid. 
Length. 
Absorption per 100. 
-A. 
1st Chamber. 2nd Chamber. 
1st Chamber. 
2nd Chamber. Both Chambers. 
2-8 
46-6 
8-6 
13-8 
13-3 
8-0 
41-4 
9-9 
12-7 
13-0 
12-2 
37-2 
110 
11-4 
13-0 
15*4 
34-0 
11*8 
121 
13-9 
28*8 
25-6 
11-7 
11-4 
13-1 
23-8 
25*6 
11-2 
11-2 
12-6 
23-8 
25-6 
10-4 
10-5 
12-0 
36*3 
13*1 
11-6 
10-0 
12-3 
Various causes have rendered these experiments exceedingly laborious. Could I have 
procured a sufficiently large quantity of gas in a single holder for an entire series of 
experiments it would not have been difficult to obtain concurrent results, but the slight 
variations in quality of the same gas generated at different times tell upon the results and 
render perfect uniformity extremely difficult to obtain. The approximate constancy of 
the numbers in the third column is, however, a guarantee that the determinations are 
not very wide of the truth. Irregularities, however, are revealed. Some remarkable ones 
occur in the case of carbonic acid, with the chambers 28-8 and 25-6 ; the absorptions in 
the first chamber varying in this instance from 11*7 to KM, and in the second chamber 
from 11*4 to 10'5, and in both chambers from 13T to 12'0. The gas which gave the 
largest of these results was generated from marble and hydrochloric acid ; the next was 
obtained from chalk and sulphuric acid, and the gas which gave the smallest result was 
obtained from bicarbonate of soda and sulphuric acid. The slight differences accom- 
panying these different modes of generation made themselves felt in the manner recorded 
in the Table. 
Table VIII. — Nitrous Oxide. 
Length. Absorption per 100. 
1st Chamber. 
2nd Chamber. 
r 
1st Chamber. 
2nd Chamber. 
Both Chambers. 
2-8 
46-6 
16-1 
32*9 
33-9 
12-2 
37-2 
23-1 
30-0 
32-0 
15-4 
34-0 
23-6 
29-6 
32*0 
17-8 
31-6 
26-2 
29-6 
32-7 
The differences arising from different modes of generation are most strikingly illus- 
trated by the powerful gases. My friend Dr. Frankland, for example, was kind enough 
to superintend for me the formation of a large holder of olefiant gas by the so-called 
“ continuous process,” in which the vapour of alcohol is led through sulphuric acid 
diluted with its own volume of water ; the following results were obtained : — 
