438 
LANDSCAPE GARDENING. 
reservoir or cistern, it ought to be of increased diameter, and 
the grating placed over it to keep out leaves and other mat- 
ters which might choke it up, ought to be semi-globular 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 ob- 
ject 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 cir- 
cular hole of the pipe. In conduit pipes, all elbows, bend- 
ings, and right angles should be avoided as much as possible, 
since they diminish the force of the water. In very 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, and protected by shafts built 
of stone or brick, and covered with moveable gratings, in or- 
der to let out the air. 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 judicious disposition of cocks and air-holes. 
Without this precaution, pipes conducted over irregular sur- 
faces will not last nearly so long as those conducted over a 
level.”- — Encycl . of Cottage , Farm : and Villa Architecture , 
page 989. 
Where the reservoir is but a short distance, as from a dozen 
to fifty yards, all that is necessary is to lay the conduit pipes 
on a regular uniform slope, to secure a steady uninterrupted 
flow of water. Owing to the friction in the pipes, and the 
pressure of the atmosphere, the water in the fountain, will 
of course, in no case, rise quite as high as the level of the 
