166 
ON THE COMBUSTION OF GAS FOR ECONOMIC PURPOSES. 
shows that with common 13-candle gas the illuminating power is increased about 4’5 
per cent, by every grain of naphtha to the cubic foot. 
On the other hand, if I destroy the solid particles by hastening their combustion, the 
light of the flame is diminished. Here, with a common Argand burner, I merely increase 
the flow of air to the gas by lengthening the glass chimney, or by enlarging the central 
aperture, or by driving the gas by great pressure through small openings, and you see 
how I destroy the light; and worse still if I mix air with the gas, so that the particles 
of carbon find themselves at once in the presence of atmospheric oxygen—there is no 
light at all. Let me blow out the gas-flame from this Argand burner, and put a piece 
of wire gauze upon the top of the glass chimney. The gas will now draw in the air 
and mix with it before it reaches the top of the chimney, and see how the light is 
destroyed. The same is the case with this burner of Professor Bunsen. It is a metal 
tube of 5 or 6 inches in length and from ^ to 1 inch diameter; the gas is admitted 
through a small aperture at the bottom of the tube, and just below this point there are 
four or five openings for the admission of air. As the gas issues from the jet and passes 
up the tube, it draws in the air, and this, mixing with the gas, burns at the top of this 
tube without any light, but with great heat. This indicates to us the disadvantage of 
allowing air, even in small proportion, to get into the gas; in fact, experiment shows 
that with common 12 -candle gas the loss of light with different proportions of air will 
as follows :— 
Loss of Light from Air in Gas. 
Per cent. Air. 
Loss per cent. 
Per cent, Air. 
Loss per 
1 . . . . 
. . 6 
8 . . . 
... 58 
2 . . . . 
. . 11 
9 . . . 
. . 64 
3 . . . , 
10 . . . 
4 . . . . 
. . 26 
15 . . . 
5 . . . . 
. . 33 
20 . . . 
6 . . . . 
. . 44 
30 . . . 
... 98 
7 . . . . 
. . 53 
40 . . . 
.The practical conclusions from these inquiries are, that gas must be burnt with such 
a proportion of air as that, on the one hand, the particles of carbon shall be intensely 
heated, and shall remain as long as possible in an ignited state, and, on the other hand, 
they must not escape unburnt. 
The difficulties in arriving at these results are almost insuperable, for every illumi¬ 
nating agent has its own particular conditions, and requires its own special appliances 
to bring out the fullest effects. 
Take for example the effect of different kinds of burners, each burning at its best,- 
with the same gas (13-candle). 
Relative Luminosity of different Burners, calculated for the same Consumption. 
Kind of Burner. Pressure at Burner. Relative Value per Foot Gas. 
Single jet . . . 0*50 .... 100 
Fishtail .... 0‘25 .... 146 
Bat’s-wing . . . 0‘18 .... 153 
Argand .... 0-17 .... 198 
Bengel .... 0T3 .... 214 
Again, the same kind of burner, but of different sizes, will give different values. 
Relative 
Luminosity of Jets of different Sizes, calcidated for the same Consumption. 
Size of Jet, Inch. 
Pressure at Burner. 
Relative Value per Foot Gas. 
0-040 . . 
• 
. 0-87 . . 
. . 100 
0-056 . . 
• 
. 0-35 . . 
. . 120 
0-083 . . 
• 
. 0-12 . . 
. . 136 
0-100 . . 
• 
. 0-04 . . 
Fishtails. 
. . 150 
0-036 . . 
• 
. 0-47 . . 
. . 100 
0-045 . . 
• 
. 0-39 . . 
. . 194 
0-056 . . 
• 
. 0-24 . . 
. . 293 
0-062 . . 
• 
. 0-39 . . 
. . 319 
