be preferred as a source
of water-supply to brooks flowing through flat agricultural land, and in
many cases, where their flow is largely due to springs, the brooks
themselves may compare favorably with springs in quality.

_Ponds or lakes._

Water may be properly taken from ponds or lakes whenever the danger from
pollution is negligible. No better source of supply can be imagined than
a pond in the midst of woods, far away from human habitation, presumably
furnishing an unlimited supply of pure soft water. Sometimes water from
such ponds contains large amounts of vegetable matter, the result of
decomposition of swampy or peaty material, as, for instance, from the
ponds in the Dismal Swamp of Virginia, so that the water has a yellow,
coffee-colored appearance. The appearance of such water is suspicious,
but it need not be feared unless something more pernicious than the
coloring matter is present.

As the country becomes more settled, ponds are more and more likely to
become contaminated and hence unfit for a water-supply, and this
possibility must be taken into account in planning for a water-supply.
It would be most shortsighted to carry a long line of pipe from a house
to a pond several miles away, only to have the pond made unfit for use
within a few years by the growth of the community around the pond. The
possibility of cooeperation ought not to be overlooked, however. It is
quite possible that half a dozen householders might be so located with
respect to each other and to a pond that an arrangement could be made
whereby the owner of a small pond would agree to fence it around and
dedicate it to the purposes of a water-supply, doing this as his share.
The others might then well afford to pipe the water to one house after
another, including that of the owner of the pond.

Water from a pond or lake has one great advantage over water from a
brook, namely, that contaminating substances in the pond settle out, so
that pond water, especially if the pond is deep, is always of much
better quality than running water. For this same reason, water taken
from a reservoir on a stream is much better water than that in the
stream above the reservoir indicates, and pollution is much less to be
feared where the reservoir exists.

_Pressure for water-supplies._

The value of a high pressure in the water-pipes of a house has been much
overestimated. For a number of years the water-supply in the writer's
residence came from a