16 Some new Researches on Flame. 
It may be concluded from the general law, that at high tem- 
peratures, gases not concerned in combustion will have less 
powers of preventing that operation, and likewise, that steam 
and vapours, which require a considerable heat for their forma- 
tion, will have less effect in preventing combustion, particularly 
of those bodies requiring low temperatures, than gases at the 
commion heat of the atmosphere. 
I have made some experiments on the effects of steam, and 
their results were conformable to these views. I found that a 
very large quantity of steam was necessary to prevent sulphur 
from burning. Oxygen and hydrogen exploded by the electric 
spark when mixed with five times their volume of steam; and 
even a mixture of air and carburetted hydrogen gas, the least 
explosive of all mixtures, required a third of steam to prevent its 
explosion, whereas 1-5th of azote produced the effect. These 
trials were made over mercury; heat was applied to water above 
the mercury, and 37-5 for 100 parts was regarded as the-cor- 
rection for the expansion of the gases. 
It is probable that with certain heated mixtures of gases, where 
the non-supporting or non-inflammable elastic fluids are in great 
quantities, combination with oxygen will take place, as in the 
instance mentioned, page 14, of hydrogen and chlorine, with- 
out any light, for the temperature produced will not be sufficient 
to render elastic media luminous ; and there are no combustions, 
‘except those of the compounds of phosphorus and the metals, 
in which solid matters are the result of combinations with oxy- 
gen. I have shown in the paper referred to in the introduction, 
that the light of common flames depends almost. entirely upon 
the deposition, ignition and combustion of solid charcoal ;_ but 
to produce this deposition from gaseous substances demands a 
high temperature. Phosphorus, which rises in vapour at com- 
mon temperatures, and the vapour of which combines with oxy- 
gen at those temperatures, as I have mentioned before, is always 
Juminous, for each particle of acid formed must, there is every 
reason to helieye, be white hot; but so few of these particles 
exist in a given space that they scarcely raise the temperature 
of .a solid body exposed to them, though, as in the rapid com- 
bustion of phosphorus, where immense numbers are Kit. in 
a small space, they produce a most intense heat, 
In all cases the quantity of heat communicated by combustion, 
will be in proportion to the quantity of burning matter coming 
in contact with the body to be heated. Thus, the blow-pipe and 
currents of air operate. In the atmosphere, the effect is im- 
peded by the mixture of azote, though still it is very great: with 
pure oxygen compression produces an immense effect, and with 
currents of oxygen and hydrogen, there is every reason to believe 
that 
