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feeing made of the proper degree of fineness,it will form a barrier for every species ofexplosion requiring temperatures higherthan those of our atmosphere: but the aper-tures must be smaller, and the radiatingsurfaces greater, in proportion to the in-flammability of the gas : and currents ofconcentrated explosive mixtures, acting evenfor any length of time, may be stopped byreduplications of wire gauze. Wire gauzefor lamps must not be made of, or coveredwith any easily combustible metal : finebrass w'ire is improper, on account of thezinc it contains, and the iron wire shouldnot be tinned. The body of the lampshould be of copper riveted together, or ofmassy cast brass or cast iron; the screwsshould fit tight; no aperture, however small,should be suffered to exist in the body ofthe lamp, and the trimming wire shouldmove through a long tight tube.

Flame, whether produced by the com-bustion of large or small quantities of ex-plosive mixture, may be always extinguishedor destroyed by certain cooling agencies;and in proportion to the heat required tocarry on the combustion, so is it more easily