1816.] On Lighting Coal Mines. 121 
If the reduced state of the flame depends, as is supposed, upon 
the quality of the air; and if in atmospheric air the adjustment of 
apertures be such as to prevent th- spontaneous extinction of the 
flame therein, other and various adjustments will be required for 
the various mixtures entering the lantern of atmospheric air and 
carbureted hydrogen gas, to prevent the successive extinctions of 
the light in the absence of all danger ; and will not this require a 
re-opening of the lantern to variously mixed airs, that will abate 
and reduce again the safety of the miner to open lamps? 
As the success of this invention is stated to depend primarily upon 
commixture with the supposed foul air within the lantern of enter- 
ing explodible gases before they reach the flame, this may best be 
effected by many small holes in the floor of the lamp at greatest 
distances from the flame. But is the air within the lantern which is 
said to reduce the flame, and which is considered capable by com- 
mixture of preventing explosions, as foul in fact as it is ‘supposed to 
be? No azote or carbonic acid gas from the combustion of the 
lamp can remain or will be found within the lantern. Their spe- 
cific gravities in their heated state at the moment of combustion 
must be considerably less than that of atmospheric air, and there- 
fore they will first rise through the chimney, and will rise urged 
upwards in a current that would carry them out of the lantern, even 
if heavier than atmospheric air. The reduction of the flame in the 
lantern, which is attributed to, and is supposed to be, evidence of 
quality, is in fact owing to the smaller quantity of air which has 
access to the flame in a current whose rapidity is diminished by the 
delayed escape, through the diminished chimney, of the heated 
azote and carbonic acid gases. The escape of these airs is retarded, 
not prevented; they must go before any other air. By their re- 
tardation, the current of air which supplies the flame is retarded, 
and the flame diminished in consequence of this diminished supply, 
but none of the azote or carbonic acid gases will remain to mix with 
the air in the lantern, to affect the flame, or to prevent explosions, 
as is supposed. And if explosion takes place within the lantern, 
will small or large holes in themselves, or elongated into tubes, 
prevent explosions of the gases from passing in train through them, 
and communicating with the external explodible mixtures from 
which they proceed? This cannot be conceived of any explodible 
mixture continued through channels of uninterrupted communica- 
tion of any dimensions. Yet is this suggested, and explosions are 
said to be “incapable of passing through small glass or metallic 
air tubes.” In the Annals of Philosophy this possible danger 
through the apertures is suggested. In the Philosophical Magazine 
for the first time air tubes of supply were contemplated. The ex- 
periment should be made. It would seem that a discharge in traig 
is to be expected through tubes of all lengths and dimensions, 
from the touch-hole of a fusil to all greater lengths and bores, 
Contrary, therefore, to what has been reasoned respecting this 
lantern, the flame is not primarily reduced by change of quality in 
Vor. VII. N° Il, I ‘ 
