through the space comprised between the two glasses of the burner.  In this way it reaches the burner, and forms an intimate mixture with the small jets of gas which compose the flame.  The gas, on leaving the supply-pipe, T, fills one of the compartments, S¹ S squared, of the heater, and then returns by the second compartment, and again descends by the casing of the supply-pipe, having its temperature still further raised by contact with the internal radiation of the flame.

Under these conditions, all the parts of the burner are supplied by heated air, and the combustion becomes very active; thus increasing the intensity of the flame, and consequently that of the light afforded, while at the same time effecting a saving of 50 per cent. of gas.  This burner may be made of any size, and for consumptions not exceeding that of an ordinary Argand.  In fact, the gas is consumed at a low pressure, escaping with no greater force than that due to the heat of the products of combustion.  It is sufficiently expanded on coming into contact with the current of hot air, the activity of which is regulated by the height of the apparatus, that is to say, by that of its two chimneys.  The mixture is made in such proportion as to obtain from the gas and air as great a degree of luminosity as possible.  The high temperature of the gas, and the independent means of heating the air and gas, constitute the essential principles of this burner.—­Journal of Gas Lighting.

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THE CLAMOND GAS BURNER.

[Illustration:  THE CLAMOND GAS BURNER.]

In this burner, which is a French invention, the light is produced by burning ordinary coal gas within a basket of magnesia, which is thereby brought to a high state of incandescence, and from which a white, steady light is radiated.  It may be said to consist of three different parts.  The first and inner part is a central column, B, of fireproof material.  The second part consists of two concentric cylinders placed round the inner column and communicating one with the other through the cross cuts, J. The third part is a china cup inclosing the other parts, and perforated with a number of holes.  The gas burns in two different places.  From A it passes directly through B, at the top of which it branches off through tubes to an annular chamber, D, from which it escapes through the openings, a, a, a, where combustion takes place.  The other combustion occurs within the circular space, G, I, between the column and the inner of the two surrounding cylinders, through two channels, E E, in the lower part of the central column.  The gas passes into a circular chamber, F F, and escapes through small holes in the upper partition of this chamber, where it burns.  The product of this combustion passes put into K, through the cross cuts, J. The air entering through the holes, H L, of the outer china cup passes along