regulated whilst running in a very simple manner. Lanchester starting system is adopted. 16 H.P. NOM. FORWARD' ENGINE The Wells Brothers, Sandiacre, near Nottingham Whilst the history of this firm as gas engine makers does not date back beyond 1889, the fact that they were the first to demonstrate the possibility of starting a gas engine by pumping a charge of gas and air into the combustion chamber in 1889, and the advantage gained by using a positive scavenging method (in 1890), and at the Crystal Palace Electrical Exhibition in 1891 being able to obtain 1 I.H.P. with 16.5 cubic feet of London gas with an engine giving 27 B.H.P., is sufficient to give them the right to take a foremost place amongst gas engine manufacturers. Fig. 45 shows their H.P. NOM. engine, which develops B.H.P. when running about 200 revolutions per minute. One of the novel features in this engine is the manner in which the mixture is admitted by means of one intermittent rotary valve, which remains at rest with the exhaust port open when making idle strokes. The method of governing is interesting in that the engine may run idle 1, 2, 3 revolutions; not as in the ordinary engine, in which the idle revolutions must be 2, 4, 6, &c. It is entirely self-contained, and does not require separate water tanks, the cooling water being contained in the bedplate, and its weight helps to steady the engine and prevents vibration. Fig. 46 represents an ordinary engine of a larger size-viz. 9 H.P. NOM. The admission and exhaust valves are arranged at an angle with the centre of the combustion chamber. The overhanging part of the cylinder is small, the main casting very rigid, and three bearings are used for the crank shaft, the worm wheels for driving the cross shaft being arranged between the two smaller ones, and the flywheels are brought close up to them on both sides. Automatic tube ignition and a modified form of inertia governor is fitted. All the engines described hitherto have been of the ordinary trunk piston type. But fig. 47 is an external, fig. 48 a longitudinal section, and fig. 49 an end view of an engine arranged with a positive scavenging arrangement, as already mentioned, is interesting as being the first successful engine using the scavenging method. The combustion chamber A is fitted with an air valve B and gas valve C, the exhaust valve D being arranged immediately |