igence and perseverance, attain a high degree
of perfection in the exercise of this faculty; yet, even the lowest must
be procured by the use of means. The art of thinking and speaking
different ideas at the same time, as we have proved, is not an
instinctive, but is wholly an acquired faculty, and must be attained by
exercise wherever it is possessed. We have instanced as examples the
case of the girl having at first to stop while dressing her doll, and
the boy while rigging his ship; but what we wish to notice here is, that
the principle is not peculiar to children, whose ideas are few, and
whose language is imperfect, but applies equally to adults, even of
superior attainments, and well cultivated minds. We have in part proved
this by the frequent defects of even learned men in conversation; but
there is good reason to conclude, that even these defects would have
been greater, if the few opportunities they have improved had been less
numerous. In short, it appears, that the successful uttering of but two
consecutive words, while the mind is otherwise engaged, must be acquired
even in the adult, by education or by discipline. This important fact in
education, might be demonstrated by numerous proofs, deduced from acts
which are commonly understood to depend altogether on habit, and where
the mind is obviously but little engaged. We shall take the case already
supposed, that of the fingering of musical instruments. The rapidity
with which the fingers in this exercise perform their office, would lead
us to pronounce it to be purely mechanical, and to suppose that the mind
was at perfect liberty to attend to any of the other functions of the
body, during the performance. But this is not the case; for although by
long practice, the operator has acquired the art of _thinking_ upon
various other subjects while playing, he finds upon a first trial, that
he is then totally unable to articulate two words in succession. Here
then is a case exactly parallel with that of the children who had to
stop to speak during their play; proving that it does not arise from the
lack of ideas, or a deficiency in words, but purely from want of
discipline and practice; because many musicians by practice, and by
practice alone, overcome the difficulty, and become able both to speak
and to play at the same time.

There is another circumstance connected with this part of our subject,
which is worthy of remark. A person who is playing on an instrume