RADIATION OP HEAT BY GASEOUS AND LIQUID MATTER. 
209 
Table IX. — Olefiant Gas. 
Length. Absorption per 100. 
1st Chamber. 
A 
2nd Chamber. 
1st Chamber. 
2nd Chamber. 
\ 
Both Chambers. 
2*8 
46*6 
34*6 
66*1 
67*7 
8*0 
41*4 
44*2 
65*3 
67*5 
15*4 
34*0 
53*6 
62*3 
67*0 
Considering the difficulty of the experiments, the agreement of the absorption of 
both chambers, the sum of which was the constant quantity 49-4 inches, must be re- 
garded as satisfactory. This is the general character of the results as long as we adhere 
to the same gas. Olefiant gas generated by mixing the liquid alcohol with sulphuric acid 
and applying heat to the mixture, gave the results recorded in the following Table : — 
Table X. — Olefiant Gas. 
Leng 
yV 
th. 
Absorption per 100. 

r~ 
1st Chamber. 
2nd Chamber. 
r~ 
1st Chamber. 
2nd Chamber. Both Chambers. 
12*2 
37*2 
54*8 
70*0 
76*3 
15*4 
34*0 
59*1 
72*7 
77*1 
19*8 
29*6 
67*8 
70*4 
77*0 
23*8 
25*6 
69*2 
70*2 
77*6 
36*3 
13*1 
72*8 
60*3 
78*8 
The absorptions of both chambers in this Table are almost exactly 10 per cent, higher 
than those found with the gas generated under Dr. Frankland’s superintendence. 
A few remarks on these results may be introduced here. In the case of carbonic oxide 
(Table VI.), we see that while a length of 2-8 inches of gas is competent, when acting 
alone, to intercept 6*8 per cent, of the radiant heat, the cutting off of this length from 
a tube 49*4 inches long, or, what is the same, the addition of this length to a tube 46*6 
inches long, makes no sensible change in its absorption. The second chamber absorbs as 
much as both. The same remark applies to carbonic acid, and it is also true within the 
limits of error for nitrous oxide and olefiant gas. Indeed it is only when 8 inches or 
more of the column have been cut away that the difference begins to make itself felt. 
Thus, in carbonic oxide, the absorption of a length of 41 '4 being 12 ‘2, that of a chamber 
49*4, or 8 inches longer, is only 12-9, making a difference of only 0*7 per cent., while 
the same 8 inches acting singly on the gas produces an absorption of 9*6 per cent. So 
also with regard to carbonic acid; a tube 41*4 absorbing 12*7 per cent., a tube 49*4 
absorbs only 13*0 per cent. — making a difference of only 0*3 per cent. As regards olefiant 
gas (Table IX.), while a distance of 8 inches acting singly effects an absorption of 44 per 
cent., the addition of 8 inches to a tube already 41*4 inches in length raises the absorp- 
tion only frQm 65*3 to 67*5, or 2*2 per cent. The reason is plain. In a length of 41*4 
the rays capable of being absorbed by the gas are so much diminished, so few in fact 
remain to be attacked, that an additional 8 inches of gas produces a scarcely sensible 
effect. Similar considerations explain the fact, that while by augmenting the length of 
2 f 2 
