_Mille carburetted gas._—In this system air is drawn into a reservoir containing a petroleum spirit by the volatilization and fall of the petroleum vapour, this vapour being heavier than air. The reservoir is placed on a higher level, and an indiarubber tube connected to its base leads the explosive mixture to the cylinder. The success of this arrangement encouraged inventors to perfect it. One of the earliest carburators by Lafroque was provided with a tiny hot-air engine, which helped to obtain a more perfect saturation of the air with the volatile spirit. In the Eclipse motors, and also in the Phœbus motors of Pluyer and Muller of Birmingham, the air and spirit vapour are mixed by an injector. The vapour is first obtained by heating the liquid spirit in a small still; it then passes by a fine nozzle across a space drawing air with it after the manner of the Giffard injector. The explosive mixture thus obtained passes into a reservoir. _Faignot apparatus._—The air is drawn in by a revolving pump and forced into a vessel, divided into several compartments, one above the other, separated by porous partitions and containing gasoline; several taps or valves cause the compartments to be alternately opened or closed, so that the mixture can always be drawn off rich in hydrocarbon vapour. This apparatus appeared in 1885 at the Antwerp Exhibition, and supplied a Bénier motor with carburetted air. It is suitable for lighting villages, country houses, etc., in fact, any places where coal gas is not laid on. The apparatus has been imitated by Polack of Hamburg and others. _Lenoir carburetted air motor._—Carburators for producing fuel for motive power have been carefully studied during the last ten years by reason of the rapidly extended use of gas motors. One of the most ingenious is due to M. Lenoir, constructed for a special motor designed by himself and constructed by Messrs. Rouart _frères_. This carburator consists of a horizontal cylinder rotated by a pinion wheel, and performing five or six revolutions a minute. Vertical perforated partitions divide the cylinder internally into several compartments, and the interior wall of the cylinder has attached to it a number of small buckets which draw up the spirit like a water-wheel, and pour it out again when they reach the summit of their path. The air and vapour are thus thoroughly mixed, and pass from thence into the cylinder. Motors supplied by such carburators have been used for agricultural operations, and also for driving small pleasure vessels, the cost of maintenance per horse-power hour being about 2½_d._