s_ requires not only
the capability of receiving an exact mental copy or imprint of all the
objects of sense or reasoning; it also requires the power of reviving or
reproducing at will all the impressions or ideas before obtained, and
the power of changing their collocations, of re-arranging them into new
forms, and of adding something to or removing something from the
original perceptions, in order to make a more perfect plan or model. If
a ship-wright, for instance, would improve upon all existing specimens
of naval architecture, he would first examine as great a number of ships
as possible; this done, he would revive the image which each had
imprinted upon his mind, and, with all the fleets which he had inspected
present to his imagination, he would compare each individual vessel with
all others, make a selection of one part from one, and of another part
from another, apply his own knowledge of the laws of moving and of
resisting forces to all, and thus create, in his own mind, the complex
idea or model of a ship more perfect than any of those he had seen.

_Now every recitation in a school, if rightly conducted, is a step
toward the attainment of this wonderful power._ With a course of studies
judiciously arranged and diligently pursued through the years of
minority, all the great phenomena of external nature, and the most
important productions in all the useful arts, together with the
principles on which they are evolved or fashioned, would be successively
brought before the understanding of the pupil. He would thus become
familiar with the substances of the material world, and with their
manifold properties and uses; and he would learn the laws,
comparatively few, by which results infinitely diversified are produced.
When such a student goes out into life, he carries, as it were, a plan
or model of the world in his own mind. He can not, therefore, pass,
either blindly or with the stupid gaze of the brute creation, by the
great objects and processes of nature; but he has an intelligent
discernment of their several existences and relations, and their
adaptation to the uses of mankind. Neither can he fasten his eye upon
any workmanship or contrivance of man without asking two questions:
first, How is it? and, secondly, How can it be improved?

Hence it is that all the processes of nature and the contrivances of art
are so many lessons or communications to an instructed man; but an
uninstructed one walks in the midst