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made with ordinary coal gas. An opportunity offering at 
the Oaks Colliery, it was thought desirable to make similar 
trials on the gas given off from the coal strata, and actually 
issuing from the Oaks Pit, 1,025 cubic feet was being given 
off per minute on the 22nd of August, 1867, the data on 
which the experiments were made. 
With the above-named arrangements of apparatus, &c, 
and a velocity of 4J miles an hour, 
The Davy Lamp exploded in from 10 to 30 seconds. 
TheClanny' do. do. 13 to 32 do. 
The Fluted Clanny improved was extinguished in from 
3 to 60 seconds, but did not explode. 
The Belgian Lamp was extinguished in from 5 to 160 
seconds, exploded in 30 seconds. 
The Cockney Lamp was extinguished in from 3 to 18 
seconds, did not explode. 
The Stephenson Lamp was extinguished in from 3 to 120 
seconds, exploded once in 45 seconds. 
At this date the fire damp contained 4 per cent, of carbonic 
acid which would seriously affect its combustible properties ; 
the gas was free from other impurities. I may here observe 
that the Stephenson and other lamps were several times 
extinguished before explosion took place, owing, it is believed, 
to its being impossible, or nearly so, to spread the gas equally 
through the entire current ; there was also a strong wind 
blowing at the time, which materially affected the steadiness 
of the current passing through the box. 
We also ascertained the following facts, viz., that the said 
fire damp issuing' through a -jj- inch pipe would ignite at a 
piece of f inch iron wire heated to bright redness when held 
in a stream of the gas. The same results were obtained with 
a \ inch round iron rod, with a bar of \\ in. square heated in 
the smith's fire to bright redness, and carried through the 
air about fifty yards, occupying about sixteen seconds in 
