Chambers, William: A Dissertation On Oriental Gardening (London: Griffin [u.a.], 1773)

vallies, that is pradised in Europe; by sorming heads os
earth or masonry at their extremities: where the soil is
too porous to hold water, they clay the bottom, in the
same manner that we do to make it tight: and in order
to prevent the inconveniences arising from flagnant waters,
they always contrive a considerable discharge to procure
motion, even where the supply is scanty; which is done
by conveying the discharged water back, through sub-
terraneous drains, into reservoirs; whence it is again raised
into the lake or river. They always give a considerable
depth to their waters, at least five or six seet, to prevent
the rising of scum, and the ssoating of weeds upon
the surface; and they are always provided with swans,
or fuch other birds as feed on weeds, to keep them
under.

In overssowing their grounds, and also in draining
them, they take all possible care not to kill many of
their old trees, either by over moistening their roots, or
draining them too much; saying, that the loss of a fine
old plant is irreparable ; that it impairs the beauty of the
adjacent