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of combustion led me, in January, 1817, toan important practical addition, foundedentirely upon a new principle.

The wire gauze lamp in its common formburns in all atmospheres that are explosive,and by suspending or placing in it a littlecage of wire of platinum or palladium fromone-sixtieth to one-seventieth of an inch inthickness, it yields a light in atmospheres toomuch contaminated with fire damp to be ex-plosive, a slow combination being occasionedby the heated platinum between the ele-ments of the gas and oxygen which producessufficient heat to keep the metals of lowconducting power and low capacity for heatpermanently ignited wherever there is airenough to support life without suffering.

I shall conclude this view by some ge-neral observations on flame and combustionwhich will shew more distinctly the causesand the limits of safety in lamps, and which'will demonstrate the danger of combinationsmade with an imperfect knowledge of theprinciples of security.

Flame may be defined to be aeriform orgaseous matter, heated to such a degree asto be luminous, and it may be produced

c