left after considering the main cranks; and taking the power to actuate the valve from any other pair of wheels is highly undesirable, both on account of the extra amount of lost motion introduced and the entire disability of the engine in case one side rod should break, if it should be the section between the wheels to which the main rod is attached and the pair carrying the eccentrics-on either side of the engine. The application of the Walschaert gear eliminates the possibility of such troubles, as this gear has no dependence on the axle for anything, and the eccentric can always be placed on the main pair of wheels.

The assertion that the Walschaert valve gear can be applied to engines of odd design without addition of complicated parts, where the Stephenson motion would have to include so much more weight of metal as to be almost prohibited, is proven in the case of this Belgian engine in Fig. 21.

In this engine live steam is used in all of the four cylinders and the operation of each is controlled by a separate piston valve of inside admission-a design of valve quite unusual in European practice—and both valves on each pair of cylinders are actuated by but one set of Walschaert's gear.

To glance at the set-up of the gear in Fig. 21,-the eccentric placed ahead of the main pin and the valvestem connected at the extreme top end of the com

bination lever-one would think that outside admission valves were indicated, but in this case things. are not as they appear to the eye: the motion of the

FIG. 24.--Side Elevation Diagram of Belgian Engine.

FIG. 25.-Plan Diagram of Above.

combination lever is not given to the stem of the outer piston valve, but is transferred through a rocker-arm to the valve operating the other cylinder of the pair—

the one inside the frame—and as the main rod from the inside cylinder is connected to the axle crank exactly opposite the main-pin connection of the outside cylinder-180 degrees apart-the set-up as shown is correct in its action on the inner half of the motion on that side of the engine.

Now, in order to supply a satisfactory motion to the valve of the outside cylinder it is only necessary to give it an exactly opposite movement to that of the inner one, and this is easily accomplished by extending the stem of the inner valve through the front head and connecting it to a lever that extends across the frame, a pin in the exact centre of the lever and a bracket attached to the frame forming its fulcrum, and to the other end of this lever is connected the extended rod from the outer valve, which also passes through its front steam-chest head. This action is the same for the pair of cylinders and valves on each side, and in the sectional views, on folding plates, Figs. 22 and 23, and the diagrams, Figs. 24 and 25, the valve connections are clearly seen.

In American practice the rocker-arm would undoubtedly be dispensed with, further simplifying the motion, and the gear so devised as to operate the outside valve and cylinder direct, using the lever connecting the extended valve-stems to actuate the inner valve.

The diameter of the cylinders is reduced to an