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Construction of Fountains for' Gardens. 



be semiglobular or conical ; so that the area of the number of 

 holes in it may exceed the area of the orifice of the conduit 

 pipe. The object is to prevent any diminution of pressure 

 from the body of water in the cistern, and to facilitate the flow 

 of the water. Where the conduit pipe joins the fountain, 

 there, of course, ought to be a cock for turning the water off" 

 and on ; and particular care must be taken that as much 

 water may pass through the oval hole of this cock as passes 

 through the circular hole of the pipe. In conduit pipes, all 

 elbows, bendings, and right angles should be avoided as much 

 as possible; since they diminish the force of the water. In 

 long conduit pipes, air holes, formed by soldering on upright 

 pieces of pipe, terminating in inverted valves, or suckers, 

 should be made at convenient distances, in order to let the 

 air out. Where pipes ascend and descend on very irregular 

 surfaces, the strain on the lowest parts of the pipe is always 

 the greatest; unless care is taken to relieve this by the judi- 

 cious disposition of cocks and air holes. Without this pre- 

 caution, pipes conducted over irregular surfaces will not last 

 nearly so long as those conducted over a level. 



The perpendicular height to which water will rise in a jet 

 has a limit, depending on the diameter of the jet, and on the 



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