THE COMBUSTION OF GAS FOE ECONOMIC FUKPOSES. 
479 
But the heat of the burning gas is more surely applied to the warming of rooms; for, 
as^ you will see by the table, a cubic foot of common gas will heat an apartment con¬ 
taining 3129 cubic feet of air 10®, and the same quantity of caunel gas will heat 
3658 cubic feet to the same extent. Other illuminating agents will, however, light for 
light, heat the atmosphere, and vitiate it to a larger extent. This is seen in the table 
which I brought under your notice at the last lecture. 
Heating and Vitiating Effects of different Illuminating Agents, when burning 
so as to give the Light of 12 Sperm Candles. 
Lbs, Water 
Oxygen 
Carb. Acid 
Air 
raised 
consumed, produced. 
vitiated, 
1 Fabr. 
Cub. Ft. 
Cub. Ft. 
Cub. Ft. 
Cannel gas . . 
. 1950 
. 3-30 
. 2-01 . 
50-2 
Common gas . . 
. 2786 
. 545 
. 3-21 . 
80-2 
Sperm oil . . . 
. 2335 
. 4-75 
. 3-33 . 
83-3 
Benzole . . . 
. 2326 
. 446 
. 3-54 . 
88-5 
Paraffin . . . 
. 3619 
. 6-81 
. 4-50 . 
112-5 
Camphine . . . 
. 3251 
. 665 
. 4-77 . 
119-2 
Sperm Candles . 
. 3517 
. 7-57 
. 5*77 . 
131-7 
Wax 5 , 
. 3831 
. 841 
. 5-90 . 
149-5 
Stearic ,, 
. 3747 
. 8-82 
. 6-25 . 
156-2 
Tallow „ 
. 5054 
. 12-00 
. 8-73 . 
218-3 
The vitiating effect is calculated on the actual loss of oxygen, and on the power which 
4 per cent, of carbonic acid has on the vital qualities of the atmosphere ; and, although 
the results indicate that there should be less discomfort in a room lighted with coal gas 
than with any other illuminating agent, yet common experience is altogether in the op¬ 
posite direction. The explanation of this is to be found not only in the fact that gas is 
used more lavishly than other agents, but also that in burning it produces a larger pro¬ 
portion of aqueous vapour, which becoming diffused into the surrounding atmosphere 
occasions great discomfort. Professor Tyndall has shown that the molecules of aqueous 
vapour are endowed with a remarkable power of absorbing the radiant heat of burning 
gas, and by thus becoming warm they create a sense of oppression; and again, when the 
warm atmosphere of a room is overcharged with moisture, it checks the action of 
vaporous or insensible perspiration, and this also causes distress. In all cases, therefore, 
where gas is largely used in rooms, provision should be made for the quick removal of 
the products of combustion. 
When the heat of gas is required for warming a room, its radiant power should be 
increased by allowing it to ignite some solid substance, for the radiant heat of a non- 
luminous flame is very insignificant. I have here a Bunsen’s burner, which gives with 
this gas the highest temperature of combustion, but the amount of heat which radiates 
from it is very small,— smaller, indeed, than is the case when the gas is burnt in the 
ordinary way, when every atom of ignited carbon becomes a centre of radiation. The 
proportions of radiant heat from the same flame under different circumstances is very 
variable. From Bunsen’s burner it is only 12, from the same gas burnt as a luminous 
flame it is 30, and with a spiral of platinum in it is 85. The introduction of solid 
matter into a non-luminous flame of high temperature changes its character altogether, 
and from the heat of convection it becomes heat of radiation. No doubt the quality of 
the vibrations is greatly changed, and they pass from the large and comparatively slow 
undulations of obscure heat to the small and quick vibrations of light; and the more 
this is effected, the greater and greater becomes the intensity of the radiant heat. 
Professor Tyndall found that the following were the quantities of radiant heat from a 
platinum spiral, at different degrees of luminosity:— 
Degrees of Heat radiated. 
Platinum spiral Feebly red.19 
do. do. Dull red.25 
do. do. Full red.62 
do. do. Orange red.88 
do, do. Yellow red.158 
do, do. Yellow white .... 200 
do. do. Blue white.276 
do. do. Intense white .... 440 
