294 DOCENDO DISCIMUS.

swer. Then he was driven to study them out. In
trying to give rules for particular cases, he learned to .
express himself with clearness, precision, and brevity.
It is one of the best results of education.

So it was in the lessons of his Bible-class in the
Sunday-school: Carl learned while he taught, and in-
structed himself in more than he gave his pupils.
Then he was led on to further attainments. If a child’s
question opened a new path, he was not content to an-
swer it; he pursued the track into other unknown
fields. Thus was he led to draft an outline map of
Palestine, and to reduce to a table all the kings of
Israel and Judah. He wrote a little memoir of the
apostle John, and borrowed books of Mr. Mill in order
to learn what the ancient writers add to the New Testa-
ment history of the beloved disciple.

Teaching young men of promise stimulates the teacher
more than the scholar. Carl had three boys who were
at surveying. It was easy to keep up with all that
they required; but he went further, and he did so with
animation and delight. He made himself better
acquainted with logarithms and geometrical problems.
He gained a minute knowledge of the theodolite and .
the sextant, and took the boys out into the fields to
‘Survey with the compass, constructing the figure in the
field, or registering the observations for subsequent
- plans: He even peeped into the volumes of Biot and -
Puisant. Carl was wide awake. His motto was,