§2 Notices respecting New Books. 
and the manual labour or machinery required to work it, ren- 
dered it inapplicable for the common uses of the collieries. 
«©] had a very portable lamp made on the principle of entire 
insulation from the atmosphere, into which the air was thrown, 
not through water, but by a small piston secured by valves ; and 
in this I found I could detonate any gaseous mixtures made ex- 
plosive by atmospherical air, without communication of the ex- 
plosion to the external atmosphere: but finding during an in- 
vestigation of the chemical properties of the fire-damp new and 
unexpected principles of security, I gave up all experiments upon 
the piston-lamp, as well as upon another contrivance of an en- 
tirely different kind described in the Appendix. 
“‘ The principles of security furnished to me by a philosophical 
inquiry into the properties of the gas are all derived from the 
general fact, that the fire-damp requires a much higher tempera- 
ture for its combustion than other inflammable gases. Hence 
small additions of azote or carbonic acid destroy the explosive 
powers of mixtures of fire-damp and air; hence explosions of 
mixtures will not take place when their quantities are small 
compared to the cooling surfaces to which they are exposed ; 
and hence one part of an explosive atmosphere of fire-damp 
may be burnt in free communication with another by certain 
cooling apertures or surfaces without any danger of explosion. 
“* As soon as I had fully developed the principles of security, 
which was towards the end of October, I hada lamp constructed, 
which I found was uniformly extinguished when introduced into y 
explosive mixtures of the fire-damp, and I communicated my 
views on the subject in two papers read before the Royal Society, 
November 9 and November 16. 
‘““ The President of the Royal Society, with his accustomed zeal 
for the promotion of every useful public object, suggested to the 
Council of that Body the propriety of giving speedy circulation 
to these inquiries, and the Council liberally sanctioned their 
immediate publication. 
“I consequently condensed the two papers into one; added 
some improvements in the construction of the lamps, and gave 
to the investigations the form in which they appear in the fol- 
lowing pages. 
«Since the paper and the Appendix have been printed, the 
consideration of the principle has led me to a discovery which 
appears the most important in the whole progress of these re- 
searches. 
** When I found that explosive mixtures admitted through 
narrow metallic canals brought in contact with flame, burnt only 
at the surface where they issued, I had hopes of keeping up a 
constant 
