393 5T2* Steam [Book VII. 



fly into the cylinder, and, condenfing the fteam, makes 

 a vacuum j then the preffure of the atmofphere bi ing- 

 ing down the pilton in the cylinder, and alfo the plug- 

 frame, another pin fixed in it catches the end of the 

 lever in its defcent, and, by prefling it down, fhuts the 

 injection -cock, at the fame time the regulator is opened 

 to admit fleam, and fo on alternately ; when the regu- 

 lator is Ihut the injection is open, and when the for- 

 mer is open the latter is fhut. 



R, the hot-well, a fmall ciftern made of planks, 

 which receives ail the wafte water from the cylin- 

 der. 



S, the fink-pit to convey away the water which is 

 iniected into the cylinder at each ftroke. Its upper 

 end is even with the infide of the cylinder bottom, its 

 lower end has a lid or cover moveable on a hinge, 

 which ferves as a valve to let out the injected water, 

 and fhuts clofe each flroke of the engine, to prevent 

 the water being forced up again when the vacuum is 

 made. 



T, the feeding-pipe, to fupply the boiler with water 

 from the hot- well. It has a cock to let in a large or 

 fmall quantity of water, as occafion requires, t make 

 up for what is evaporated j it goes nearly down to the 

 boiler bottom. 



U, two gage cocks, the one larger than the other, 

 to try when a proper quantity of water is in xhe boiler: 

 upon opening the cocks, if one gives fteam and the 

 other water, it is rights if they both give fteam, there 

 is too little water in the boiler; and if they both give 

 water, there is too much. 



W, a plate which is fcrewed on to a hole on the fide 

 of the boiler, to allow a paflagc into the boiler for the 

 convenience of cleaning or repairing it. 



X, the fleam-clack or puppet valve, which is a 



brafs 



