his command.

The application of this principle to the elements of general knowledge
is equally necessary, as its application to written language. The
difficulty of remembering the many thousands of unconnected characters
in Chinese literature, is an exact emblem of what will always be the
case with children in respect to their general knowledge, when this
principle of association, or grouping, is neglected. Adults acquire and
retain a large portion of _their_ knowledge, as we shall afterwards see,
by the principle of classification and analysis; but _children_ are not
as yet capable of this; and they must receive their knowledge by the
grouping of a few simple elements previously known, or they will not be
able to receive and retain knowledge at all. The amount of this
knowledge also, it should be kept in mind, is not at all in proportion
to the number or the variety of the elements of which that knowledge is
composed. We have formerly alluded to this, and it may be farther
illustrated by a circumstance of daily occurrence. A seaman when he
observes a vessel at a distance knows her class and character in an
instant, whether she be a sloop or a brig, a schooner or a ship, and he
forms an instantaneous idea of all her parts grouped into a whole. His
memory, instead of being harassed in remembering the shape, and place,
and position of each of its several parts, is relieved of the whole by
the operation of this principle of association. The whole rigging, about
which his mind is occupied, is composed of only _three_ elements,--ropes,
and spars, and sails,--with each of which he has long ago made himself
familiar. All the remaining parts of this kind of knowledge are a mere
matter of grouping. By previously observing the varied arrangement of the
spars, and ropes, and sails, on the several masts of the different kinds
of vessels, he has already grouped them into one whole, and each is
remembered by itself without effort, and without mistake. They are
retained, as it were, painted by the imagination upon the memory, and may
at any after period be recalled and reviewed at pleasure. Hence the sight
of a vessel in the distance calls up the former pictures to the mind, and
enables the practised eye of the mariner to decide at once as to the kind
and character of what he so imperfectly sees.--This helps also to explain
the reason why children are so gratified with pictures when presented to
the eye; and why they are best pleased