As the production of water gas implies the absorption of a large quantity of sensible heat, it is accompanied with a rapid fall of temperature in the chambers, B', and eventually also in the generator, A, while at the same time the chambers, B, are but moderately heated by the sensible heat of the current of gas produced. When this cooling has continued so long that the temperature in the generator, A, is no longer high enough to allow the fuel to decompose the steam with ease, the valve, J', of the pipe, P', that leads the steam is closed, as is also the valve, K, of the pipe, Q, while the valves, L and H, of the pipes, R and N, are opened. After this the valve, I', is opened, and a current of air is let in through the pipe, O'. This air, upon traversing the chambers, B' and T', is raised to a high temperature through the heat remaining in these chambers, and then enters at the bottom of the generator, through the flue, E'. The air gas that now makes its exit from the pipe, M, in the chamber, T, meets another current of air coming from the pipe, N, and is thus burned. The products resulting from such combustion pass into the chambers, B, and then into the chimney, through the pipe, R. The temperature then rapidly lowers in the chambers, B', and rises no less rapidly in the generator, A, while the chambers, B, are soon heated to the same temperature that first existed in the chambers, B'. As soon as the desired temperature is obtained in the generator, A, and the chambers, B, the air is shut off by closing the valve, I', of the pipe, O'; the valve, F', of the flue, E', is also closed, the valves, G' and K', of the pipes, M' and Q', are opened, the valves, G, H, and L, of the pipes, M, N, and R, are closed, and the valve, F, of the flue, E, and the valve, J, of the pipe, P, are opened. A current of steam enters the apparatus through the pipe, P, traverses the chambers, B, and enters the generator through the flue, E. The gas produced makes its exit from the generator, passes through the pipe, M', and the chambers, T' and B', and the pipe, R, and enters the gasometer through the pipe, Q'.
When the chamber, B, and the generator, A, are again in so cool a state that the fuel no longer decomposes the steam easily, the valves are so maneuvered as to stop the entrance of the latter, and to send a current of air into the apparatus in the same direction that the steam had just been taking. The temperature thereupon quickly rises in the generator, A, while, at the same time, the combustion of the air gas produced soon reheats the chambers, B'. The cooled products of combustion go, as before, to the chimney. The position of the valves is then changed again so as to send a current of steam into the apparatus in a direction contrary to that which the air took in the last place, and the water gas obtained again is sent to the gasometer.