ced in the middle of an
attic floor without causing serious settlement, if not actual breaking
through, of the floor.

[Illustration: FIG. 56.--Construction of a wooden tank.]

A good way of placing such a tank is to nail the floor joists onto the
bottom of the rafters, so that a truss is formed, and the box or tank is
properly supported on the floor and also hung from the rafters by iron
straps bolted both to tank and rafters. If possible, this tank should be
placed directly over a partition carried through to the cellar, in which
case no settlement is possible.

_Main supply pipe._

The main supply pipe, except when pressure is very great, is most
satisfactory when made of three-quarter-inch galvanized iron pipe. Even
with a high pressure, half-inch pipe is unsatisfactory because of the
great velocity with which the water comes from the faucets and because
the high pressure causes the packing in the faucets to wear out rapidly.
This three-quarter-inch pipe should have a stop-and-waste, as it is
called, just inside the cellar wall, so that if the house is not
occupied at any time, the valve may be shut and the water in the pipes
drawn off, to prevent possible freezing. The pipe should never be
carried directly in front of a window or along the sill of the building
unless protected by some kind of wrapping. The laterals and the
different fixtures are taken off from this main supply pipe as it rises
through the house, and the pipe is capped at the top.

_Hot-water circulation._

To provide hot water, a branch must be taken off at the level of the
kitchen stove and run into the hot-water boiler at or near the bottom.
The circulation in the tank and through the house is then provided for
by a separate circuit running from the bottom of the hot-water tank to
the water-back and back into the tank at a point about halfway up. The
house circuit is then run from the top of the boiler around through the
house, and if a return pipe is provided, it comes back and enters at the
bottom. This hot-water pipe is also of galvanized iron and should be of
the same size as the main supply pipe (see Fig. 57).

[Illustration: FIG. 57.--Hot-water attachment to the kitchen stove.]

The fixtures may be as elaborate as the purse and taste will allow, but
some general instruction may not be out of place. There are many types
of faucets, all good, and differing from each other only in some minor
detail of construction. Experience with the