new Inflammable Air or Gafs, Sec. 389 
I found that tether, in which as much urinous phof- 
phorus is diffolved as will make it luminous in the dark, 
when fome drops are poured upon water; is very hr irk. 
in taking fire, when employed for an inflammable air 
piftol; but that the experiment, when repeated, will be 
apt to fail, becaufe the phofphoric acid which remains in 
the piftol, and by its' nature attracts the humidity of the 
atmofphere, will foon fill the infide of the piftol with a 
coat of moifture, and prevent the electrical fparlc from 
kindling the inflammable air. 
It appeared, that a little camphire diffolved in tether 
increafes its explofive force, and makes it lefs apt to fail. 
As this inflammable air is heavier than common air, 
it is clear, that the mouth of the air piftol fhould be kept 
upwards at the time of charging it; whereas it is better 
to invert the piftol when the ordinary inflammable airs 
are employed, which, being fpecifically lighter than com- 
mon air, rife of themfelves in the piftol when its mouth 
is placed inverted upon the orifice of the veflel which 
contains them. 
It is true, that the fqueezing the elaftic gum bottle, 
when placed upon the piftol, forces fome of the inflamma- 
ble gafs out of it, which is loft in the common air; but 
notwithftanding this wafte, the inflammable air which 
Vol. LXIX. Fff 
remains 
