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dangerous parts of the British, collieries.Yet instances of explosion have been knownfrom the steel mill, and it required manuallabour for its use. In Flanders amadou orfungus tinder had been occasionally em-ployed in dangerous parts of the mine, butthe light yielded by this substance was muchtoo feeble to be used for working the mines,and only enabled the miners to find theirway for particular occasions.

M. de Humboldt, the justly celebratedphilosophical traveller, in 1796 conceivedand executed the plan of a lamp* for giv-ing light in mines where a common candlewould not burn or produce explosion; butit was founded on the principle of entire insu-lation from the air, and could burn only for ashort time till the air contained within it wasexhausted. A lamp upon a plan similar asto insulation, was contrived by Dr. Clanny,in 1815, but he supplied his light with airfrom the mine through water by bellows,and it went out in explosive atmospheres,and to be employed required to be workedby hand, or by machinery; and neither

* Journal ties Mines, Tom, VIII. p. S39.