This kiln was invented and constructed by M. Fillard (successor of M. Gastelier at Fresnes), one of the most ardent defenders of gas firing, who has succeeded, after persevering attention, in devising a really practical form of kiln.

This rectangular kiln does not differ in its main features from the kiln which we have described in detail, except as to its central portion. The smoke channel has above it another, stretching the whole length of the kiln and serving for distribution of the gas. The arched roofs are pierced, as in ordinary continuous kilns, with a series of heating holes closed by movable lids. The channel conducting the gas has also in its upper part orifices corresponding to each row of holes; these orifices are also closed by movable lids. The combustion of the gas takes place in hollow pipes, called "chandelles," made of refractory clay, and pierced with holes. These pipes, which are formed of several parts fitting one within the other, are movable and placed below the stoke holes. They are put into communication with the gas channel, when necessary, by means of a pipe with several branches which are fitted to the opening of the channel and the corresponding stoke holes; these branch tubes are fitted with valves which permit of the communication between the "chandelles" and the gas conduit being shut off.

As for the gas generator, Figs. 225 to 227 show its construction : it has two furnaces working simultaneously. The gases pass into a chamber which acts as a gasometer, and afterwards enter the central conduit of the kiln.

The generators may be placed anywhere; most generally they are at the end of the kiln (Figs. 228, 229), but if space does not allow of this, they may be put at the side of the kiln. Water is always kept beneath the fire-bars; this water evaporates, and in passing through the incandescent mass gives out water gas.

Gas Generator. (Scale of 11 millimetres to the metre).

Fig. 225. Transverse Section of a Furnance.

Elevation of a Furnace.

Fig. 226. Elevation of a Furnace.

Fig. 227. Longitudinal Section of a Furnace.