49 
Sir H. Davy's researches on flame . 
its flame extinguished, even though the tube was furnished 
with the wire when the pressure was below 
The flame of carbonic oxide which, though it produces 
little heat in combustion, is as inflammable as hydrogene, 
burned when the wire was used, the pressure being 
The flame of sulphuretted hydrogene, the heat of which is 
in some measure carried off by the sulphur produced by its 
decomposition during its combustion in rare air, when burned 
in the same apparatus as the olefiant and other gases, was 
extinguished when the pressure was y. 
Sulphur, which requires a lower temperature for its com- 
bustion than any common inflammable substance, except 
phosphorus, burned with a very feeble blue flame in air rare- 
fied fifteen times, and at this pressure the flame heated a wire 
of platinum to dull redness, nor was it extinguished till 
the pressure was reduced to T.* 
Phosphorus, as has been shown by M. Van Marum, burns 
in an atmosphere rarefied 60 .times; and I found that phos- 
phuretted hydrogene produced a flash of light when admitted 
into the best vacuum that could be made, by an excellent 
pump of Nairn’s construction. 
The mixture of chlorine and hydrogene inflames at a much 
lower temperature than that of hydrogene and oxygene, and 
produces a considerable degree of heat in combustion ; it was 
* The temperature of the atmosphere diminishes in a certain ratio with its 
height, which must be attended to in the conclusions respecting combustion in the 
upper regions of the atmosphere, and the elevation must be somewhat lower than in 
arithmetical progression, the pressure decreasing in geometrical progression. 
There is, however, every reason to believe, that the taper would be extinguished 
at a height of between 9 and 10 miles, hydrogene between 12 and 13, and sulphur 
between 15 and 16. 
MDCCCXVII. H 
