54 Notices respecting New Books. 
into an atmosphere consisting of about 1 of coal-gas and 11 of 
air; but it soon lost this temperature; and in other experiments 
made with smaller wicks in a dark room, I have seldom seen the 
wire dull red: bnt as no explosion ever took place in an atmo- 
sphere made explosive by coal-gas, the circumstance, for reasons 
that will be fully stated in the communication made to the Royal 
Society *, wiil hold good with much more certainty of the fire- 
damp. ' 
**T own | expected an explosion in the instance when I saw 
the wire-gauze red hot ; but the mass of heated matter was pro- 
bably too small to heat considerably the portion of gas in con- 
tact with it, and the cool air must have entered principally at 
this part of the wire- gauze cylinder, and must speedily have re- 
duced the temperature ; and I have since found that a red-hot 
wire of less than the )th of an inch does not explode mixtures 
of coal-gas and air. 
“ When I took the wire-gauze lamp out of the most explosive 
mixture before it had consumed much of the inflammable gas, 
the mixture usually was explosive by the flame of the taper; but 
the explosive power of a mixture of 12 or 13 parts of air to one 
of gas was very soon destroyed by the combustion in the cylinder 
lamp; and even when it was withdrawn almost immediately, 
the taper burnt in the mixture merely with an enlarged flame. 
“‘It is needless to dwell upon the practical applications of 
these facts ; many of them will be immediately perceived. Wire- 
gauze may be substituted for horn or glass in the safe-lanterns 
or safe-lamps to be used in the collieries, and no air feeders be- 
low the flame will be necessary. The wire-gauze admits a free 
circulation of air, and it emits considerably more light than 
common horn. I have had small cylindrical caps of wire- 
gauze made to fit small lamps by a screw, which are almost as 
portable as a common candle without a candlestick ; and which 
are trimmed and supplied with oil through safe apertur es with- 
out the necessity of taking off the cap. <A similar cap may be 
used with the common candles of the colliers introduced ig an 
aperture made tight with moist pipe-clay. 
“* Brass-wire gauze of the proper degree of fineness is manu- 
factured for the use of mills and for sieves. I found gauze 
which contained 3600 apertures in a square inch sufficiently fine 
to prevent explosion used as a cylinder; but it did not bear the 
proof of a concenired explosion from a close glass vessel. 
Gauze of 5000 apertures to the square inch stood, however, this 
severe test. I have generally used gauze of 6400 apertures 5 
and I have seen plated wire-gauze, which, I am told, is sold at 
* Sce Phil. Mag. vol. xlvi p. 444—58. 
Edinburgh, 
