68 
Sir H. Davy’s researches on flame. 
IV. Some general observations , and practical inferences. 
The knowledge of the cooling power of elastic media in 
preventing the explosion of the fire-damp, led me to those 
practical researches which terminated in the discovery of the 
wire-gauze safe-lamp ; and the general investigations of the 
relation and extent of these powers, serves to elucidate the 
operation of wire-gauze and other tissues or systems of 
apertures permeable to light and air, in intercepting flame, 
and confirms the views I originally gave of the phenomenon. , 
Flame is gaseous matter heated so highly as to be lumi- 
nous, and that to a degree of temperature beyond the white 
heat of solid bodies, as is shown by the circumstance, that air 
not luminous will communicate this degree of heat.* When 
an attempt is made to pass flame through a very fine mesh of 
wire-gauze at the common temperature, the gauze cools each 
portion of the elastic matter that passes through it, so as to 
reduce its temperature below that degree at which it is lumi- 
nous, and the diminution of temperature must be proportional 
to the smallness of the mesh and the mass of the metal. The 
power of a metallic or other tissue to prevent explosion, will 
depend upon the heat required to produce the combustion as 
compared with that acquired by the tissue ; and the flame of 
the most inflammable substances, and of tho <e that produce 
most heat in combustion, will pass through a metallic tissue 
that will interrupt the flame of less inflammable substances, 
or those that produce little heat in combustion. Or the tissue 
* This is proved by the simple experiment of holding a fine wire of platinum 
about the of an inch from the exterior of the middle of the flame of a spirit lamp, 
and concealing the flame by an opaque body, the wire will become white hot in a 
space where there is no visible light. 
