CONSTRUCTION OF AN HYDRAULIC APPARATUS. 29 



to communicate with the branch 3 ; the aperture of the key 

 du<5t, which before correfponded with the end of the branch 2, 

 is now placed under the orifice of the rarefying tube, and the 

 opening which was there before, is turned to the branch,3. 



At the time when all communication between the veflel 

 and fyphon is interfe&ed, one of the claws or pins on the far- 

 ther fide of the lower wheel, opens the valve of the air pipe 

 in the veflel A, and immediately after it the valve of the pipe 

 for letting out water is deprefled by a claw on the nearer fide. 

 This Jail valve will make little refiltance, as the whole prefliire 

 of the atmofphere was removed by opening the fmall pipe firft ; 

 for this purpofe it has a feparate valve. 



The raited water flows out of A while B is filling. 

 When the veflels D and E are emptied, the large weight 

 moves the wheels and the cock ; the valves of B are opened 

 in the fame order as thofe of A, which being again connected 

 with the fyphon, is. filled while B is emptied. 



In actual work the receptacle of raifed water muft be placed Remarks and 

 under the veflels, the axis of the lower wheel may extend oWervat,ons - 

 acrofs the receptacle, and have two arms or levers, fixed in a 

 proper pofition to deprefs the valves, while the wheel itfelf 

 will move on the outfide. The key or plug of the cock turned 

 by the axis of the higher wheel, fhould move very true in its 

 barrel. The higher wheel fhould be made light if the key of 

 the cock is fixed faft to its avis. The key or plug fhould be 

 frequently taken out and rubbed with tallow -, its tightnefs 

 may be adjufted by a fcrew fixed in a proper frame and moved 

 by a weight. When any repair is requifite, the cock in the 

 air pipe above A muft be turned. 



A fyphon fix inches in diameter will require its air pipe to 

 be about one inch and a half in diameter. 



By a fyphon of thefe dimenfions water may be raifed to the 

 height of fixty feet, if the vertical water pipe of the veffel B, 

 be placed in the cittern which receives the raifed water from 

 A, and the branch of the air pipe 3 be carried to the top of 

 the veffel B. Both the veflel and the air pipe fhould be made 

 fomething lefs on account of the greater body of air to be ra- 

 refied. The air pipe fhould reach confiderably above the 

 veflel, or it muft have a float valve, to prevent any wafte of 

 the railed water. 



If 



