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COAL MINES OF

be happy to hear of the ultimate experimentsfurnishing security, as I have no doubt moredifficulty will be found in contending withgas in a mine, than in experimenting upon itin the laboratory ; as I have had this suffi-ciently testified by Dr. Clanny’s experiments,who, though he obtained the gas immediatelyfrom a colliery only five miles from Sunder-land, found much difference in its nature afterletting it remain a day or two. The fire-dampfrom the Hepburn Colliery is full of inflamma-ble particles : when burnt it gives a brilliantlambent flame, and emits a stream of brightred scorifications or sparks, which, accordingto Black, are small combustible substanceswhich explode on inflammation ; and not un-frequently, when ignited by the spark of asteel-mill, communicate explosion to the sur-rounding air. I did not find these scorifica-tions so numerous in gases from other mines ;but few give out gas wholly free from them.

It must be remembered that Dr. Clanny’soriginal lamp was heavy, strong, and durable,and yet objections were made to it as insecure,from the danger of being broken by splinters ofcoal falling down, &c. as described in his paperto the Royal Society.* How; Sir Humphry

* See page 1 16 ,