502 
the top of the lantern, which was 
made tight in a pneumatic rim 
containing a little oil ; the upper 
and lower apertures in the chim- 
ney were about % of an inch: the 
lamp, which was fed with oil, 
gave a steady flame of about an 
inch high, and half an inch in dia- 
meter. When the lantern was 
slowly moved, the lamp continued 
to burn, but more feebly ; and 
when it was rapidly moved, it 
went out. To obviate this cir- 
cumstance, I surrounded the bot- 
tom of the lantern with a perfo- 
rated rim; and this arrangement 
perfectly answered the end pro- 
posed. 
“T had another chimney fitted 
to this lantern, furnished with a 
number of safety tin-plate tubes 
of the sixth of an inch in diame- 
ter and two inches long ; but they 
diminished considerably the size 
of the flame, and rendered it more 
liable to go out by motion; and 
the following experiments appear 
to show, that if the diameter of 
the upper orifice of the chimney 
be not very large, it is scarcely 
possible that any explosion pro- 
duced by the flame can reach it. 
‘‘T threw into the safe-lantern 
with the common chimney, a mix- 
ture of 15 parts of air and one of 
fire-damp ; the flame was imme- 
diately greatly enlarged, and the 
flame of the wick seemed to be 
lost in the larger flame of the fire- 
damp. I placed a lighted taper 
above the orifice of the chimney : 
it was immediately extinguished, 
but without the slightest previous 
increase of its flame, and even 
the wick instantly lost its fire by 
being plunged into the chimney. 
“Tintroduced alightedtaperinto 
a close vessel containing 15 parts 
ANNUAL REGISTER, 1815. 
of air and one of gas from the 
distillation of coal, suffered it to 
burn out in the vessel, and then 
analysed the gas. After the car- 
bonic acid was separated, it ap- 
peared by the test of nitrous gas 
to contain nearly 2 of its original 
quantity of oxygen ; but detona- 
tion with a mixture of equal parts 
of hydrogen and oxygen proved 
that it contained no sensible quan- 
tity of carburetted hydrogen gas. 
“Tt is evident, then, that when, 
in the safe-lantern, the air gradu- 
ally becomes contaminated with 
fire-damp, this fire-damp will 
be consumed in the body of the 
lantern; and that the air passing 
through the chimney cannot con- 
tain any inflammable mixture. 
‘<I made a direct experiment on 
this point. I gradually threw an 
explosive mixture of fire-damp 
and air into the safe-lantern from 
a bladder furnished with a tube 
which opened by a large aperture 
above the flame; the flame be- 
came enlarged, and by a rapid jet 
of gas I produced an explosion in 
the body of the lantern ; there 
was not even a current of air 
through the safety tubes at the 
moment, and the flame did not 
appear to reach above the lower 
aperture of the chimney ; and the 
explosion merely threw out from 
it a gust of foul air: 
* Thesecond safety-lantern that 
I have had made is upon the same 
principle as the first, except that 
instead of tubes, safety canals are 
used, which consist of close con- 
centric hollow metallic cylinders 
of different diameters, and placed 
together so as to form circular ca- 
nals of the diameter of from =", to 
~ty of an inch, and an inch and 4% 
long, by which air is admitted in 
