274 
PROCEEDINGS 1849—1858. 
worked in the iieiglibourliood of Banisley, which often covered an 
area of 1,000 to 1,500 acres. If they started at the engine pit and 
pushed their working to the up-cast before they fairly began to get 
the coal, they would be very expeditious to complete the preliminary 
work in two years and a half. That was precisely the most 
dangerous period of a mine, because of the difficulty of expelHng the 
foul air before they had got their straight work completed. After 
some further observations from Mr. Brooke, Mr. Sykes Ward, and 
Mr. Carter, Mr. Brackenridge replied that by the mode he recom- 
mended there could be no danger in the lower part of the mine, as 
there would be no old workings in which gas would be generated, and 
that the quantities given off in making the shaft would be so small 
that they could be easily dealt with. 
Mr. F. H . Pearce, of Bowling, gave the result of some experi- 
ments in the ventilation of a pit one hundred and twenty yards deep, 
of which he had charge. On account of some defect in the pumps 
water had accumulated in the mine and ascended some distance up 
the shaft, thus completely stopping the ventilation, and rendering 
any effort to repair the damage hopeless from the accumulation of 
choke-damp. He contrived to pass a small steam pipe to the bottom 
of the seven-inch pipe used for lifting the water, and on turning on 
the steam the air was dra^\'n from the shaft and purified in an almost 
extrordinary manner. At the same meeting Mr. J. Jebson, of Mold 
Green, near Huddersfield, also read a paper on the ventilation of 
mines, in which he contended for the old system of working and 
ventilation possessing greater practical advantage than would be 
likely to accrue from the adoption of the plan suggested by Messrs. 
Carter and Brackenridge. 
Mr. Robert Hunt, F.R.S., Keeper of the Mining Records, con- 
contributed a paper on the statistical returns of the mineral produce 
of Yorkshire for the year 1857. The production of lead ore amounted 
to 12,045 tons, from which 7,875 tons of lead had been obtained. 
Of the latter amount, Cononley contributed 388 tons, and the mines 
in the valley of the Wliarfe 1,336 tons. The largest amount, however, 
w^as obtained from Swaledale and Wensleydale, which contributed 
5;365 tons. The iron ore of Yorkshire is the most metalliferous 
