i j6 Sir Humphry Davy on the combustion of 
Iron wire gauze of and of 24 apertures to the inch, or 
of 57 6 to the square inch, appeared safe under all circum- 
stances in explosive mixtures of coal gas. I kept up a con- 
tinual flame in a cylinder of this kind, 8 inches high and 2 
inches in diameter, for a quarter of an hour, varying the pro- 
portions of coal gas and air as far as was compatible with their 
inflammation ; the top of the cylinder, for some minutes, was 
strongly red hot, but though the mixed gas was passed 
rapidly through it by pressure from a gasometer and a pair 
of double bellows, so as to make it a species of blast furnace, 
yet no explosion took place. 
I mentioned in my last communication to the Society, that 
a flame confined in a cylinder of very fine wire gauze, did 
not explode a mixture of oxygene and hydrogene, but that 
the gases burnt in it with great vivacity. I have repeated 
this experiment in nearly a pint of the most explosive mixture 
of the two gases ; they burnt violently within the cylinder, 
but, though the upper part became nearly white hot, yet no 
explosion was communicated, and it was necessary to with- 
draw the cylinder to prevent the brass wire from being 
melted. 
These results are best explained by considering the nature of 
the flame of combustible bodies, which, in all cases, must be con- 
sidered as the combustion of an explosive mixture of inflammable 
gas, or vapour and air ; for it cannot be regarded as a mere 
combustion at the surface of contact of the inflammable matter : 
and the fact is proved by holding a taper or a piece of burning 
phosphorus within a large flame made by the combustion of 
alcohol, the flame of the candle or of the phosphorus will 
