methods of lighting the mines without producing its explosion. 1 5 
1 1 
inch; this stops explosions as well as long tubes or canals, 
and yet admits of a free draught of air. 
Having succeeded in the construction of safe lanterns and 
lamps, equally portable with common lanterns and lamps, 
which afforded sufficient light, and which bore motion per- 
fectly well, I submitted them individually to practical tests, 
by throwing into them explosive atmospheres of fire-damp 
and air. By the natural action of the flame drawing air 
through the air canals, from the explosive atmosphere, the 
light was uniformly extinguished; and when an explosive 
mixture was forcibly pressed into the body of the lamp, the 
explosion was always stopped by the safety apertures, which 
may be said figuratively to act as a sort of chemical fire sieves 
in separating flame from air. But I was not contented with 
these trials, and I submitted the safe canals, tubes, and wire 
gauze fire sieves, to much more severe tests : I made them the 
medium of communication between a large glass vessel filled 
with the strongest explosive mixture of carburetted hydro- 
gene and air, and a bladder ~ or ■§■ full of the same mixture, 
both insulated from the atmosphere. By means of wires 
passing near the stop-cock of the glass vessel, I fired the 
explosive mixture in it by the discharge of a Leyden jar. 
The bladder always expanded at the moment the explosion 
was made ; a contraction as rapidly took place; and a lambent 
flame played round the mouths of the safety apertures, open 
in the glass vessel ; but the mixture in the bladder did not 
explode : and by pressing some of it into the glass vessel, 
so as to make it replace the foul air, and subjecting it to the 
electric spark, repeated explosions were produced, proving 
the perfect security of the safety apertures ; even when acted 
