352 PEOFESSOE TYNDALL’S CONTEIBTTTIONS TO MOLECULAR PHYSICS. 
Table XXIV. — Radiation of heat through Vapours. Source, a highly luminous jet 
of gas. 
Name of vapour. 
Deflection. 
Absorption. 
White-hot spiral. 
Bisulphide of Carbon . . . 
. 8*9 
9-8 
2-9 
Chloroform 
. 10-9 
12-0 
5-6 
Iodide of Methyl 
. 15-4 
16-5 
7-8 
Iodide of Ethyl 
. 17-7 
19-5 
12-8 
Benzol 
. 20-0 
22-0 
16-5 
Amylene 
. 27-5 
30-2 
22-7 
Formic Ether 
. 31-5 
34-6 
25-1 
Sulphuric Ether 
. 32-5 
35-7 
25-9 
Acetic Ether 
. 34-2 
38-7 
27-2 
Total heat 
. 53-8 
100*0 
It is interesting to compare the heat emitted by the white-hot carbon with that 
emitted by the white-hot platinum ; and to facilitate the comparison, I have placed 
beside the results in the last Table those recorded in Table XIII. The emission from 
the flame is thus proved to be far more powerfully absorbed than the emission from the 
spiral. Doubtless, however, the carbon, in reaching incandescence, passes through lower 
stages of temperature, and in those stages emits heat more in accord with the vapours. 
It is also mixed with the vapour of water and carbonic acid, both of which contribute 
their quota to the total radiation. It is therefore probable that the greater accord 
between the periods of the flame and those of the vapours is due to the slower periods 
of the substances which are unavoidably mixed with the body to which the flame mainly 
owes its light. 
The next source of heat employed was the flame of a Bunsen’s burner, the tempera- 
ture of which is known to be very high. The flame was of a pale-blue colour, and 
emitted a very feeble light. The following results were obtained : — 
Table XXV. — Radiation of heat through Vapours. 
Bunsen’s burner. 
Source, pale-blue flame of 
From Table XXIY. 
Name of vapour. 
Deflection. 
Absorption. 
Luminous jet of gas. 
Chloroform 
O 
.... 5-0 
6-2 
12*0 
Bisulphide of Carbon 
. . . . 9-0 
11*1 
9*8 
Iodide of Ethyl . . 
.... 11-3 
14-0 
19*5 
Benzol 
.... 14*5 
17*9 
22-0 
Amylene .... 
.... 19-6 
24-2 
30*2 
Sulphuric Ether . . 
.... 25*8 
31-9 
35*7 
Formic Ether . 
.... 27-0 
33-3 
34*6 
Acetic Ether . . . 
36-3 
38*7 
Total heat .... 
, . . . 50-6 
100*0 
100*0 
