Fig. 71 is a side elevation of the cylinder, with the valve connections with the governor. S is the steam pipe; s, s’ handles to the steam valves, and e, e’ to the exhaust valves, shown in dotted line in fig. 70.  The handles to the exhaust valves are connected directly to a rocking plate R, to which motion is given by a connection x, with an eccentric on the engine shaft.  When once set, therefore the movement of the exhaust valves is constant, and they will always be opened and closed at the same point of the stroke.  Connected with the rocking plate R, and on opposite sides of its centre, the same as the exhaust valve connections, there are two levers, vibrating on a centre c, of which one only is shown, as it covers the other; to the upper ends of these levers pawls are attached, one end of which rests on the stems or rods connected with the handles s, s’, of the steam valves; on these stems there are notches against which the pawls strike, and as the levers vibrate inward they push back the stems and thereby open the valves, and this continues for the whole length of the inward motion of the levers, or till the outer extremities of the pawls come in contact with the end of the short lever l, which, pushing down the outer end of the pawls, relieves the stems at the other ends, and the valve stem returns to its place through the force of springs attached to the outer extremities of the valve stems a, are cylindrical guides to the valve stems, at the inner extremities of which are air cushions.  The lever l is connected directly with the governor.  As the balls rise, they depress the extremity, which comes in contact with the pawls sooner, and thereby shut the valves earlier; and on the contrary when the balls are depressed, the valves remain open longer; as the pawls come in contact with the stems always at one point, the steam valves open constantly, but are closed at any point by the relief of the pawls, according to the speed of the governor.

Fig. 71 represents, partly in section and partly in plan, the cylinder, steam chests, valves, &c., of one of the Woodruff & Beach high pressure Engines, Wright’s patent.

Fig. 72 represents, in elevation, the cam shaft, to the upper end of which, not shown in the drawing, is attached the ordinary centrifugal governor.  The cylinder, steam chests, valves, &c., being similar to those of other engines, need no special notice; but the cam for opening and closing the steam valves, fig. 72, requires particular attention, as it embodies a beautiful and simple device for cutting off the steam with certainty at any part of the stroke, the motion being produced automatically by the action of the governor on this cam, throwing it more or less out of centre with the spindle of the governor, as the rotation of the balls is less or more rapid, the eccentricity of the cam determining the amount of steam admitted to the working cylinder of the engine.  To produce this effect the cam is made as follows: