that the wheat can not get
food enough from the soil to yield a maximum crop, not because there is
not food enough in the field, but the roots of the wheat are so
constituted that they can not gather it up; while clover-roots, foraging
in the same soil, can find all they want."

"Clover," said the Deacon, "is the scavenger of the farm; like a pig, it
gathers up what would otherwise be wasted."

"Of course, these illustrations," said the Doctor, "do not give us any
clear idea of _how_ the clover-plants take up food. We must recollect
that the roots of plants take up their food in solution; and it has just
occurred to me that, possibly, Mr. Lawes' experiments on the amount of
water given off by plants during their growth, may throw some light on
the subject we are discussing."

"Mr. Lawes found," continued the Doctor, "that a wheat-plant, from March
19 to June 28, or 101 days, evaporated through its leaves, etc., 45,713
grains of water; while a clover-plant, standing alongside, and in
precisely similar condition, evaporated 55,093 grains. The clover was
cut June 28, when in full bloom. The wheat-plant was allowed to grow
until ripe, Sept. 7. From June 28 to Sept. 7, or 72 days, the
wheat-plant evaporated 67,814 grains."

"One moment," said the Deacon; "as I understand, the clover-plant
evaporated more water than the wheat-plant, until the 28th of June, but
that during the next 71 days, the wheat-plant evaporated more water than
it had during the previous 101 days."

"Yes," said I, "and if these facts prove nothing else, they at least
show that there is a great difference between wheat and clover. I was at
Rothamsted when these experiments were made. During the first nine days
of the experiment, the clover-plant evaporated 399.6 grains of water;
while the wheat-plant, standing alongside, evaporated only 128.7 grains.
In other words, the clover-plant evaporated three times as much water as
the wheat-plant. During the next 31 days, the wheat-plant evaporated
1,267.8 grains, and the clover-plant 1,643.0 grains; but during the next
27 days, from April 28 to May 25, the wheat-plant evaporated 162.4
grains of water per day, while the clover-plant only evaporated 109.2
grains per day. During the next 34 days, from May 25 to June 28, the
wheat-plant evaporated 1,177.4 grains per day, and the clover-plant
1,473.5 grains per day."

"In June," said the Deacon, "the clover evaporates ten times as much
water per day as it did in