nce of privies, as shown by Fig. 36, the
water should not be used for domestic supply, although a number of
individuals may have been using the water for years without bad effects.
It is a case in which prevention is much wiser than cure, and while
economy and convenience may indicate such a polluted stream to be a
desirable source of supply, a proper regard for health conditions will
rule it out absolutely.

CHAPTER VIII

_WATER-WORKS CONSTRUCTION_

Construction methods and practices which lend themselves to the
development of the water-supply for an individual house may be divided
into three parts, namely:--

(1) Construction at the point of collection, whether this point
be a well, spring, brook, or reservoir;

(2) The pipe line leading from the collection point to the
buildings;

(3) Constructions involved in the house, other than the
plumbing fixtures.

Taking up these different points in order, we may note at the outset
that it is possible to employ either very simple or very complicated
construction.

_Methods of collection of water._

The common method is to lay a galvanized iron pipe in a ditch as far as
a spring and there to protect the end of the pipe with a sieve or a
grating and to leave it exposed in the water with no efforts expended on
the spring itself. In a brook with waterfalls or with good slope, it is
not uncommon to project a large pipe or a wooden trough into the stream
at the top of a waterfall and so carry a certain amount of the water
into a tub or basins from which the small pipe leads to the house. On
the shores of a lake or pond the galvanized iron pipe is laid out on the
bottom of the lake with the end protected by a strainer.

In all these cases the simplest method is the best, provided the supply
of water is not needed in the winter; but such simple methods as just
described fail when frost locks up the surface flow of the stream. Then
the pipe throughout its entire length must be in a trench below the
frost line at the entrance to the spring as elsewhere. To permit this,
the spring must also be deep, or else so inclosed that the pipe leading
into the spring can be covered by earth banked up against it. Not long
ago the writer saw a pipe taking water from a small lake recently
improved by a stone wall. Instead of conveying the water-pipe down under
the wall the unwise stone mason had built the wall around the pipe and
the pipe line was f