classes should be trained to military precision and exactness in these
manipulations. What I mean by this may perhaps be best illustrated by
describing a case: it will show, in another branch, how much will be
gained by acting upon numbers at once instead of upon each individual in
succession.

Imagine, then, that a teacher requested all the pupils of his school who
could write to take out their slates at the hour for a general
exercise. As soon as the first bustle of opening and shutting the desks
was over, he looked around the room, and saw some ruling lines across
their slates, others wiping them all over on both sides with sponges,
others scribbling, or writing, or making figures.

"All those," says he, speaking, however, with a pleasant tone and with a
pleasant look, "who have taken out any thing besides slates, may rise."

Several, in various parts of the room, stood up.

"All those who have written any thing since they took out their slates
may rise too, and those who have wiped their slates."

"When all were up, he said to them, though not with a frown or a scowl,
as if they had committed a great offense,

"Suppose a company of soldiers should be ordered to _form a line_, and
instead of simply obeying that order they should all set at work, each
in his own way, doing something else. One man at one end of the line
begins to load and fire his gun; another takes out his knapsack and
begins to eat his luncheon; a third amuses himself by going as fast as
possible through the exercise; and another still, begins to march about
hither and thither, facing to the right and left, and performing all the
evolutions he can think of. What should you say to such a company as
that?"

The boys laughed.

"It is better," said the teacher, "when numbers are acting under the
direction of one, that they should all act _exactly together_. In this
way we advance much faster than we otherwise should. Be careful,
therefore, to do exactly what I command, and nothing more.

"_Provide a place on your slates large enough to write a single line_,"
added the teacher, in a distinct voice. I print his orders in Italics,
and his remarks and explanations in Roman letters.

"_Prepare to write_.

"I mean by this," he continued, "that you place your slates before you
with your pencils at the place where you are to begin, so that all may
commence precisely at the same instant."

The teacher who tries such an experiment as this will find