tion:--when we listen, the neck is
stretched forward, and such position enables us to collect those
vibrations of sound, that would be otherwise inaudible. We are not
unaccustomed to describe the higher and more felicitous productions of
intellect, as a vigorous grasp of the mental powers, or as a noble
stretch of thought: but to infer that the mind itself was capable of
being extended, would be to invest it directly with the properties of
substance, and at once plunge us into the grossest materialism. The
perfection of this voluntary direction, or, as it has been termed,
faculty of attention, consists in intensity and duration. Of the former
there can be no admeasurement, excepting by its effect, which is
recollection: its duration can be well ascertained. The faculty of
attention in the human mind may be exerted in two ways; first, by the
organs of sense to the objects of perception; and, secondly, by the mind
to the subjects of its recollection; and this latter exercise of
attention, as will be hereafter explained, seems to be in a very great
degree peculiar to man, and to be nearly wanting in animals.

According to the nature and constitution of the human mind, the
effective duration of the attention seems to be very limited: if the eye
be steadily directed to any particular object, after a few seconds, it
will be found to wander; and if the mind be exerted on the subjects of
its recollection, there is very soon perceived an interruption, from the
intrusion of irrelevant thoughts. The effective duration of the
attention will much depend on the superior capacity, nature, or
constitution of the intellect itself; but still more on the manner in
which these habits of attention are exercised; for, by proper
cultivation, its duration may be considerably protracted. As a proof of
the limited endurance of the faculty of attention in ordinary minds,
allow the following experiment to be made.

Let two ordinary persons, A. and B., take a map of a district with which
they are unacquainted, and let each be allowed half an hour to study the
map. Desire A. to fix his attention undeviatingly to the map for this
time; and at its expiration, the map being withdrawn, request him to put
on paper the relative situations and names of the different places; and
for the performance of his task, allow him another half hour. As the
experiment has been repeatedly made, it may be confidently predicted,
that A. would exhibit a very incorrect co