96

Suppose a flame divided by the wiregauze into smaller flames, each flame mustbe extinguished in passing its aperture tillthat aperture has attained a temperaturesufficient to produce the permanent com-bustion of the explosive mixture.

A flame of sulphur may be made muchsmaller than that of hydrogene, that of hy-drogene smaller than that of a wick fedwith oil, and that of a wick fed with oilsmaller than that of carburetted hydrogene;and a ring of cool wire which instantly ex-tinguishes the flame of carburetted hydro-gene, only slightly diminishes the size of aflame of sulphur of the same dimensions.

Where rapid currents of explosive mix-tures are made to act upon wire gauze, itis of course much more rapidly heated;and therefore the same mesh which arreststhe flames of explosive mixtures at rest,

inch in diameter, made by fusing the end of a wire bebrought near a flame of one-thirtieth in diameter, it willextinguish it when cold at the distance of its own di-ameter ; let it be heated, and the distance will diminishat which it produces the extinction ; and at a white heatit does not extinguish it by actual contact, though at adull red heat it immediately produces the effect.