ANALYSIS OF PRIME-MOVERS.
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ratchet-train ( 126), formed from the train (C^'P-^r with the addition of a slide-valve. Steam is the ratchet, the piston the click-frame (the links a and c respectively in Figs. 352 355). B, the valve-gear, is the director, and consists of a train (C^P- 1 )* formed by the eccentric, eccentric-rod, slide-rod and frame. It drives the slide-valve, which is itself a combination of four separ-. ate valves, representing the ratchet-pawls ; in the Corliss and
A B
FIG. 360,
similar engines the four valves appear separately. C is the regu- lator, consisting of a common centrifugal governor (the kinematic constitution of which we must here leave unexamined), with a throttle-valve and gearing.
The feed-pump I) requires special notice. It might be considered as a machine by itself, for which the engine was the prime-mover, but if we assume that the engine has a boiler for itself alone we may treat the pump as forming a part of the engine. It would
