May. How much water would an acre of clover
evaporate?"

"Let Charley figure it out," said the Doctor. "Suppose each plant
occupies 10 square inches of land; there are 6,272,640 square inches in
an acre, and, consequently, there would be 627,264 clover-plants on an
acre. Each plant evaporated 1,473.5 grains per day, and there are 7,000
grains in a pound."

Charley made the calculation, and found that an acre of clover, from May
25 to June 28, evaporated 528,598 lbs. of water, or 15,547 lbs. per day.

A much more accurate way of ascertaining how much water an acre of
clover evaporates is afforded us by these experiments. After the plants
were cut, they were weighed and analyzed; and it being known exactly how
much water each plant had given off during its growth, we have all the
facts necessary to tell us just how much a crop of a given weight would
evaporate. In brief, it was found that for each pound of dry substance
in the wheat-plant, 247.4 lbs. of water had been evaporated; and for
each pound in the clover-plant, 269.1 lbs.

An acre of wheat of 15 bushels per acre of grain, and an equal weight of
straw, would exhale during the spring and summer 177-3/4 tons of water,
or calculated on 172 days, the duration of the experiment, 2,055 lbs.
per day.

An acre of clover that would make two tons of hay, would pass off
through its leaves, in 101 days, 430 tons of water, or 8,600 lbs. per
day--more than four times as much as the wheat.

These figures show that, from an agricultural point of view, there is a
great difference between, wheat and clover; and yet I think the figures
do not show the whole of the difference. The clover was cut just at the
time when the wheat-plant was entering on its period of most rapid
growth and exhalation, and, consequently, the figures given above
probably exaggerate the amount of water given off by the wheat during
the early part of the season. It is, at any rate, quite clear, and this
is all I want to show, that an acre of good clover exhales a much larger
amount of water from spring to hay-harvest than an acre of wheat.

"And what," said the Deacon, who was evidently getting tired of the
figures, "does all this prove?"

The figures prove that clover can drink a much greater quantity of water
during March, April, May, and June, than wheat; and, consequently, to
get the same amount of food, it is not necessary that the clover should
have as much nitrogen, phosphoric acid, potash, etc