en soils, a still
greater depth may not be expedient, to be compensated by increased
distance.

DISTANCES DEPEND UPON CLIMATE.

Climate includes the conditions of temperature and moisture, and so,
necessarily, the seasons. In the chapter which treats of _Rain_, it will
be seen that the quantity of rain which falls in the year is singularly
various in different places. Even, in England, "the annual average
rain-fall of the wettest place in Cumberland is stated to be 141 inches,
while 19-1/2 inches may be taken as the average fall in Essex. In
Cumberland, there are 210 days in the year in which rain falls, and in
Chiswick, near London, but 124."

A reference to the tables in another place, will show us an infinite
variety in the rain-fall at different points of our own country.

If we expect, therefore, to furnish passage for but two feet of water in
the year, our drains need not be so numerous as would be necessary to
accommodate twice that quantity, unless, indeed, the time for its
passage may be different; and this leads us to another point which
should ever be kept in mind in New England--the necessity of quick
drainage. The more violent storms and showers of our country, as
compared with England, have been spoken of when considering _The Size of
Tiles_. The sudden transition from Winter to Summer, from the breaking
up of deep snows with the heavy falls of rain, to our brief and hasty
planting time, requires that our system of drainage should be efficient,
not only to take off large quantities of water, but to take them off in
a very short time. How rapidly water may be expected to pass off by
drainage, is not made clear by writers on the subject.

"One inch in depth," says an English writer, "is a very heavy fall of
rain in a day, and it generally takes two days for the water to drain
fully from deep drained land." One inch of water over an acre is
calculated to be something more than one hundred tons. This seems, in
gross, to be a large amount, but we should expect that an inch, or even
two inches of water, spread evenly over a field, would soon disappear
from the surface; and if not prevented by some impervious obstruction,
it must continue downward.

It is said, on good authority, that, in England, the smallest sized
pipes, if the fall be good, will be sufficiently large, at ordinary
distances, to carry off all the surplus water. In the author's own
fields, where two-inch tiles are laid at four feet depth