THE CORNISH ENGINE. 11 
#’ An iron catch attached to the plunger pole and projecting on each side thereof, 
and which rests on the spring beams J J when the engine works to the 
full extent of its out-door stroke. 
RR The beam. 
K The main gudgeon. 
M The plummer block. 
N The catch to prevent the engine going too far in-doors. 
O The spring beams for the catch to rest upon. 
P Cross girder to support the spring beams. 
PLATE IIL 
Fig. 1. Plan of the boiler house and four cylindrical boilers, two of which, 
together with the warming tube, are shown in section. 
Fig. 2. Plan of the engine house and Cornish engine, with pump and stand 
pipe. 
Fig. 3. Longitudinal section of the cataract for opening the equilibrium 
valve. 
Fig. 4. Elevation of the cataract for opening the exhaustion and steam 
valves. 
Although figs. 1 and 2 form one connected plan of the boiler and engine 
houses, they are referred to as two separate figures, for the sake of using, 
as far as possible, the letters of reference which indicate the corresponding 
parts in the other Plates. 
Fig. 1. Nos. 1, 2, 3, and 4, the boilers. 
These numbers correspond with the numbers given in Table I., Dimensions 
of Boilers, Appendix, page 34 of my Paper on these engines.* 
A The warming tube into which the water is injected by the feed pump through 
the feed pipe a. 
bb The pipe through which the water passes from the warming tube to each 
boiler. It is fitted with stop valves at 4 A. 
B B B B Internal tubes of the boilers. 
CC Fire doors. 
DD Grates. 
4 See Wicksteed on the Cornish and Boulton and Watt Pumping Engines.