when a
person learns something, and then makes use of it, he will never forget
it. I might study surveying a whole year in school, but if I did not go
out into the fields to apply what I learned to actual practice, it would
do me little good; and it is so with every thing."

"There is a good deal of truth in that," replied Charlie; "but there is
a difference in the ability of persons to use what they acquire. Some
persons have a very poor way of showing what they know."

It was true that Nat did not gorge his mind by excessive reading. Some
readers can scarcely wait to finish one book, because they hanker so for
another. They read for the mere pleasure of reading, without the least
idea of laying up a store of information for future use. Their minds are
crammed all the time with a quantity of undigested knowledge. They read
as some people bolt down a meal of victuals, and the consequences are
similar. The mind is not nourished and strengthened thereby, but is
rather impaired finally by mental indigestion.

Coleridge divides readers into four classes. "The first," he says, "may
be compared to an hour-glass, their reading being as the sand; it runs
in, and it runs out, and leaves not a vestige behind. A second class
resembles a sponge, which imbibes every thing, and returns it nearly in
the same state, only a little dirtier. A third class is like a
jelly-bag, which allows all that is pure to pass away, and retains only
the refuse and the dregs. The fourth class may be compared to the slave
in the diamond mines of Golconda, who, casting aside all that is
worthless, preserves only the pure gem." Nat was a reader of the latter
class, and, at the same time, saved every gem for _use_. He had no
disposition to _hoard_ knowledge, as the miser does his gold. He thought
it was designed for use as really as a coat or hat--an idea that does
not seem to have entered the heads of many youth, of whom it may be
said, "their apparel is the best part of them."

It is as necessary to have a fixed, noble purpose behind a disposition
to _read_, as behind physical strength in secular pursuits, otherwise
what is read will be of comparatively little service. The purpose with
which a thing is done determines the degree of success therein, and the
principle applies equally to reading. Nat's purpose converted every
particle of knowledge acquired into a means of influence and usefulness,
so that he made a given amount of knowledge go further tow