When the small burner, I, in the lower chamber is lighted, the products of combustion issue by the orifice, O, of the compartment, terminating in a needle like that of the steam injector; and the jet draws along the air entering the apertures, PP, above the cone.  The gas from the pipe, arriving from the annular space, L, fills the two lateral pockets shown in dotted lines, and passes through the orifices, AA¹, which communicate with the upper chamber of the burner.  The manner in which it is conveyed thence to the tubular arrangement has already been described.

Fig. 2 shows a more simple method of carrying out the same principle, and of effecting a considerable saving in gas for a given intensity of light.  In this form, a wick, T, impregnated with an alkaline earthy solution, a few seconds after lighting, affords a focus of white light remarkable for its steadiness and brilliancy.  A draught of air is created by a jet of gas issuing from the hollow needle, B, and passing through the vessel, D, which is provided with orifices, O, for the entrance of air.  The air and gas pass from D into C, whence (after their intimate mixture is effected) they pass into the tubular arrangement, F, at the top of which combustion takes place.

To regulate the proportions in which the air and gas should mingle, in order that the combination should be as intimate as possible, the air inlet is made variable by a perforated collar, which permits of the orifices, O, being more or less covered.  The other proportions of the burner—­that is to say, the relative capacity of the two compartments and the length of the hollow needle—­are determined by the sectional area of the supply-pipe for the gas, which is admitted under moderate pressure.  Instead of a wire-gauze cap, impregnated with a solution of metals or of salts, two fine platinum wires may be used—­one bent into the form of a semicircle of about an inch radius, and the other (of slightly larger diameter) rolled spirally round the former.  When both ends of the two wires are connected with the upper portion of the tubular arrangement (which in this case is flattened), and the gas is ignited at the burner, the metallic arc becomes red hot, and then brightly incandescent, emitting a light, less brilliant indeed than with magnesia, but of remarkable steadiness.

In this case the production of light is chiefly due to the fact that calorific condensation, caused by the use of the helicoidal coil surrounding the curved wire, prevents loss of heat in this conductor.  In these forms of high-power burner, in which the gas is used directly for the production of light, the difficulty generally encountered of heating the air (present in a larger volume than the gas) has been successfully overcome.