336 
EXPLANATION OF THE PLATES. 
eating by means of beveled wheels with the crank shaft. Four arms, 9, 10, 11, 
and 12, are fixed to the rods v v and w w, for the purpose of moving the valves, 
and a lever or handle (13), turning on a pin screwed on the pipe E, is used to open 
and shut the steam valves when the engine is first set to work; (see art. 566 ;) the 
steam gauge (21) is for measuring the pressure of the steam above that of the 
atmosphere, (art. 558.) and the condenser gauge (24) is for measuring the force of 
the vapour in the condenser, (art. 559.) 
Fig. 3. 4. 5. and 6. represent the four-way cock as executed by Maudslay. 
Fig. 5. is the plan taken at the horizontal line D E, in Fig. 3. and 4., which are 
sections through the steam cock. In these figures E is the steam pipe, and F the 
pipe leading to the condenser G. Fig. 4. is the steam cock or cone ground into its 
seat, and provided with a grease cup H to afford a regular supply. 
Fig. 6. is a plan of the upper side of the steam cone. See art. 457 and 
Plate xv.