RADIATION OF HEAT BY GASEOUS AND LIQUID MATTER. 
223 
Collecting the radiations from the second chamber for the lengths 34 inches and 
131 inches together in a single Table, we see at a glance how the radiation is affected 
by varying the length. 
Table XLVIII. 
Dynamic radiation of various vapours at 05 
inch pressure and a common thickness of 
34 inches. 13 - 1 inches. 
Bisulphide of carbon . . . 
. 14-2 
O 
9-0 
Benzol 
. 34-0 
15-1 
Iodide of ethyl ..... 
. 38-8 
19-0 
Chloroform 
. 41-0 
19-0 
Alcohol 
. 53-8 
34-9 
Sulphuric ether ..... 
. 68-0 
36-5 
Formic ether 
. 68-0 
41-0 
Acetic ether . ..... 
. 73-9 
41-0 
At a pressure of 0-1 
of an inch. 
Alcohol 
. 35-7 
1T5 
Boracic ether 
. 61-0 
31-6 
The extraordinary energy of boracic ether as 
a radiant may be 
inferred from the last 
experiment. Although attenuated to 3-jjoth of an atmosphere, its thinly scattered mole- 
cules are able to urge the needle through an arc of 61 degrees, and this merely by the 
warmth generated on the entrance of dry air into a vacuum. 
Arranging the gases in the same manner, we have the following results : — 
Table XLIX. 
Dynamic radiation of gases at 1 at. 
pressure and a common thickness of 
~\ 
34 inches. 
13-1 inches. 
Carbonic oxide . . . 
. . . 24-4 
16°*6 
Carbonic acid . . . 
. . . 23-3 
17-5 
Nitrous oxide . . . 
. . . 31-7 
22-0 
Olefiant gas .... 
. . . 68-0 
65-0 
The influence of tenuity which renders the vapour at 0‘5 of an inch a more open 
screen than the gas at 30 inches is here exhibited. In the case of the vapour, a greater 
length is available for radiation than in the case of the gas, because the radiation from 
the hinder portion of the column of vapour is less interfered with by the molecules in 
front of it than is the case with the gas. By shortening the column we therefore do 
more injury to the vapour than to the gas ; by lengthening it we promote the radiation 
from the vapour more than that from the gas. Thus while a shortening of the gaseous 
mdccclxiv. 2 H 
