depends upon a number of factors. Increasing the
diameter of very deep wells does not seem to have any marked effect in
increasing the supply. Thus, a two-foot well gives only from fifteen
to thirty per cent more water than a three-inch-pipe well. This rule
does not seem to apply to shallow wells of large diameter, for here we
find that the yield is about in proportion to the diameter of the
well.

It is interesting to note the fact that wells located near the
seashore, within the influence of the tide, vary in the hourly flow.
According to Dr. Honda, of the University of Tokio, there is "a
remarkable concordance between the daily variations in the level of
the tides and the water level in wells." The water in wells one mile
from the seashore was found to stand highest at high tide. The daily
variation amounted to sixteen centimeters, or a little over six
inches. A similar variation was observed by the writer in some flowing
wells located on the north shore of Long Island. Dr. Honda found also
that the water level in wells varied with the state of the barometer,
the water level being lowered with a rise in the barometer.

Where a large supply is wanted a series of wells may be driven, and,
as the expense involved is considerable, it is always advisable to
begin by sinking a smaller test well to find out whether water may be
had.

Ground water may also be recovered from water-bearing strata by
arranging horizontal collecting galleries with loose-jointed sides
through which the water percolates. Such infiltration galleries have
been used in some instances for the supply of towns and of
manufacturing establishments, but they are not common for the supply
of country houses.

_Laws Regulating Appropriation of Water_

Persons contemplating the establishment of a system of water supply in
the country should bear in mind that the taking of water for supply
purposes is, in nearly all States, hemmed in by legal restrictions.
The law makes a distinction between subterranean waters, surface
waters flowing in a well-defined channel and within definite banks,
and surface waters merely spread over the ground or accumulated in
natural depressions, pools, or in swamps. There are separate and
distinct laws governing each kind of water. It is advisable, where a
water-supply problem presents itself, to look up these laws, or to
consult a lawyer well versed in the law of water courses.

If it is the intention to take water from a