on the Combustion of Gaseous Mixtures. 23 
the increase of temperature was not sufficient to render the 
gaseous matters themselves luminous; yet still it might be 
adequate to ignite solid matters exposed to them. I had de- 
vised several experiments on this subject. I had intended to 
expose fine wires to oxygen and olefiant gas, and to oxygen 
and hydrogen during their slow combination under different cir- 
cumstances, when | was accidentally led to the knowledge of the 
fact, and, at the same time, to the discovery of a new and cu- 
rious series of phenomena. 
I was making experiments on the increase of the limits of the 
combustibility of gaseous mixtures of coal gas and air by in- 
erease of temperature. For this purpose, I .introduced a small 
wire-gauze safe-lamp with some fine wire of platinum fixed 
above the flame, into a combustible mixture containing the 
maximum of coal gas; and when the inflammation had taken 
place in the wire-gauze cylinder, I threw in more coal gas, ex- 
pecting that the heat acquired by the mixed gas in passing 
through the wire-gauze would prevent the excess from extin- 
guishing the flame. The flame continued for two or three se- 
conds after the coal gas was introduced; and when it was ex- 
tinguished, that part of the wire of platinum which had been 
hottest remained ignited, and continued so for many minutes, 
and when it was removed into a dark room, it was evident that 
there was no flame in the cylinder. 
It was immediately obvious that this was the result which I 
had hoped to attain by other methods, and that the oxygen and 
coal gas in contact with the hot wire combined without flame, 
and yet produced heat enough to preserve the wire ignited, and 
to keep up their own combustion. J proved the truth of this 
conclusion by making a similar mixture, heating a fine. wire of 
platinum and introducing it into the mixture. It immediately 
became ignited nearly to whiteness, as if it had been itself in 
actual combustion, and continued glowing for a long while; and 
when it was extinguished, the inflammability of the mixture was 
found entirely destroyed. 
A temperature much below ignition only was necessary for 
“producing this curious phenomenon, and the wire was repeatedly 
taken out and cooled in the atmosphere till it ceased to be visibly 
red; and yet when admitted again, it instantly became red hot. 
The same phenomena were produced with mixtures of olefiant 
gas and air, carbonic oxide, prussic gas and hydrogen, and in 
the last case with a rapid production of water; and the degree 
of heat I found could be regulated by the thickness of the wire. 
The wire, when of the same thickness, became more ignited in 
ae than in mixtures of olefiant gas, and more in mixtures 
of olefiant gas than in those of gaseous oxide of carbon. 
BA4 When 
