_Taylor gas-producing plant modified by Wimand._—There exist a number of systems of gas-producers which are not so well known as those which we have already described, but which are none the less interesting. The most important of these is a modification by Wimand of the Taylor system, in which the boiler is discarded, and replaced by a jacket or vessel surrounding the generating plant and heated by the waste gases. The hot water trickles down over a column of coke, and meets at the base the current of air passing towards the generator; the air is therefore heated, and becomes saturated with water vapour. This device can be applied to any generator. _Kitson gas-producer._—A rotating hearth is provided, as in other systems already described. The air is driven by a steam injector through holes in it, and the steam is supplied from a spiral coil situated in the fire-brick lining of the generator. A second tube through which the steam passes acts as a superheater. The steam enters a reservoir chamber at the side of the generator, from which it passes out again to fulfil its functions. There is therefore no fan needful, and the generating furnace is not liable to become fouled. The price of the plant is moderate. _Loomis gasogene._—This apparatus aspirates its air and draws it completely through a layer of carbon from top to bottom. The generator is open at the top, and instead of the usual grate at the bottom it is provided with a cone-shaped base instead. The air drawn in combines with the carbon during its downward journey, and then passes through a cooling tower surrounded by a water jacket which acts as a boiler. The heat extracted from the gas is therefore used to produce steam, which drives an engine working the pump which aspirates the air. The exhaust steam from this engine passes into the incandescent fuel and is decomposed, forming hydrogen and carbon monoxide. The valves which govern the supplies of air and steam are so arranged that producer gas or water gas, or both at once, may be generated at will. One particular plant is known to have worked unceasingly for two years without stopping, but in this case it did not supply a gas engine, in fact, we believe that this system has not been applied for driving motors at all as yet. _Wilson gas-producer._—The generator is broader than it is high, and it is possible to use in it all sorts of cheap coal and coke. A window is provided, so that the attendant can see if the fuel is sticking and not settling down properly. The air is blown into the centre of the hearth by a steam injector at a low pressure of about two inches of water or less. Stoking is effected by turning spiral grate bars which rid the fire of clinkers and ashes. The air is heated by waste gases from the motor, a process which gives a slight gain in economy.