HYDRAULICS. 209 



cocks c and d, are united by the handle // called 

 the regulator. 



The mode of operation is as follows. Let the 

 regulator be so placed, that the steam-cock c be 

 open and the injection-cock d shut : put water 

 into the boiler a, and make it boil. The steam 

 from it will enter the pipe b, and fill the receiver, 

 first driving out the air which it before contained ; 

 a considerable quantity of steam will be at first 

 condensed by the cold sides of the receiver, but it 

 being at length warmed, the steam will proceed 

 into the rising-pipe, lifting up the valve i. When 

 this is perceived to be the case, by the rising-pipe 

 feeling warm, and hearing the valve i rattle, the 

 communication is now to be cut oft* from the boiler, 

 by shutting the steam-cock c, the injection-cock d 

 being also shut. The receiver now gradually cools, 

 and the steam included in it condenses into water. 

 When this is the case, as the air was at first driven 

 out by the steam, and cannot return again, all the 

 cocks being shut, a vacuum is formed in the re- 

 ceiver ; consequently, there is nothing to counter- 

 balance the pressure of the atmosphere, which 

 acting upon the water in the well, forces it up the 

 rising-pipe, and fills the receiver. The steam-cock 

 is now opened ; and the steam from the boiler 

 rushing in with great violence, presses upon the 

 surface of the water in the receiver, and forcing it 

 through the pipe s, into the rising-pipe, causes it 

 to shut the valve ?i, and open the other valve i ; 

 and provided the steam be sufficiently strong, wilt 

 force it up the rising-pipe to the top k, where it is 

 delivered. The cock c is kept open until all the 

 water be driven out of the receiver, and it is again 

 filled with steam. The regulator is now applied, 

 which shuts the steam-cock, whilst at the same 

 vol. i. p 



