COMBUSTIBILITY OF GASES. 
32 
nitrous muriatic and sulphurated hydrogen gases might, per- 
haps, under these circumstances, appear as inflammable as 
phosphorated hydrogen gas. 
Well-conducted experiments of this kind promise to 
afford results of great interest to science. 
Rarefactionby y. Instead of rarefying the gaseous mixtures by means of the 
heat has the . _ . 7 i 6 1 
same effect as air-pump, I made use of heat, 
diminished 
pressure. Experiments. 
The tube was filled with mercury, and inverted in a bason of 
the same metal. I passed up one inch of detonating gas, com- 
posed of 'wo parts of common air, and one of pure hydrogen. 
By means of a moveable spirit lamp, I heated the upper part 
of the tube until the gas occupied four times its original volume. 
As the gases were not previously dried, they must have con- 
tained much moisture, which favours the dilatation j for, 
without the presence of water, so great a dilatation could not, 
perhaps, have been effected at that temperature. I then 
passed electric sparks from the conductor of the machine, and 
by Jeyden vials of middling size, without ever succeeding in 
setting fire to the dilated gas. As soon as the gaseous mixture 
began to cool, and the space it occupied no longer exceeded 
three times its original volume, it took fire by a weak spark, 
and it was easy to observe, that the inflammation was propor- 
tioned to the density of the gas. 
By continuing to cause the electric fluid to act upon the 
dilated gas to a point which rendered the subsequent inflam- 
mation impossible, I had farther occasion to observe a quiet 
composition of water. 
Flame applied VI. In order to determine how the detonating acid, in this 
instead of elec- s t a te of dilatation, would comport itself at the approach of a 
lighted taper, I filled a tube to one-fourth, which I heated so 
as to cause all the mercury to descend, and part of the gas be- 
gan to escape from the tube. At this moment I approached 
a lighted taper, but it did not rake fire. I left the tube in the 
mercury, and after cooling, I closed the lower orifice with my 
finger, then inverted the lube, and the gas took fire with explo- 
sion, on the approach of a lighted candle. 
This experiment seems to prove, that caloric cannot be con- 
sidered otherwise than as an indirect cause of explosion. By 
ils 
