Large removable plates cover the top of the water jackets so that it is a simple matter to clean out the water space in case that it becomes coated with deposits from the water. This is an important feature as a great many of the heating troubles may be overcome by having access to the interior of the water jacket. The water outlet pipes connect with the jacket covers. Both cam shafts are driven by the gears at the right which connect with the crank shaft pinion. Fan is belt driven from an extension to the cam shaft. All bearings are supplied with oil by a high pressure force feed pump, the crank pins receiving their supply through channels drilled in the crank shaft and pin, which in turn are connected to the oil supply of the main bearings, no dependence being placed on a splash system. After leaving the bearings, the oil drops into the crank case and drains into the sump shown at the left of the longitudinal section. From the sump, the oil returns to the oil pump from which point it is returned to the circulating system under high pressure. (46) Stationary Four Cylinder Engine. An English stationary engine, the Browett-Lindly, similar in many respects to the automobile engines just described, is shown in longitudinal and cross-section by Figs. 20 and 21. This is of the “L” type of valve arrangement, but instead of having the valves side by side as in the preceding case, the inlet valve is placed over the exhaust as will be seen from the cross-section view. [Illustration: Fig. 21. Cross-Section Through Browett-Lindly Engine. ] The exhaust valve is operated directly from the cam shaft by the push rod as in the auto engines, but the inlet valve receives its motion through a long vertical rod and horizontal lever, the latter being located on the cylinder head as shown by the longitudinal section. A supplementary valve is mounted loosely on the stem of the inlet valve, and this valve is held against the seat of the gas inlet port by a short spring. [Illustration: Fig. 20. Section Through Browett-Lindly Four Cylinder Stationary Engine. ] A collar on the main valve spindle opens this gas valve, and, by adjusting the position, a certain amount of lag can be given, so that air first enters the cylinder and then, by further travel of the main valve, the gas valve opens and the combined charge is taken in. This prevents any “back fires” as the gas and air are entirely separated until they enter the cylinder.