mense help in some professions
stands to reason, but in ordinary social life the possession of a
high visualising power, as of a high verbal memory, may pass quite
unobserved. I have to the last failed in anticipating the character
of the answers that my friends would give to my inquiries, judging
from my previous knowledge of them; though I am bound to say that,
having received their answers, I could usually persuade myself that
they were justified by my recollections of their previous sayings
and conduct generally.

The faculty is undoubtedly useful in a high degree to inventive
mechanicians, and the great majority of those whom I have questioned
have spoken of their powers as very considerable. They invent their
machines as they walk, and see them in height, breadth, and depth as
real objects, and they can also see them in action. In fact, a
periodic action of any kind appears to be easily recalled. But the
powers of other men are considerably less; thus an engineer officer
who has himself great power of visual memory, and who has
superintended the mathematical education of cadets, doubts if one in
ten can visualise an object in three dimensions. I should have
thought the faculty would be common among geometricians, but many of
the highest seem able somehow to get on without much of it. There is
a curious dictum of Napoleon I. quoted in Hume's _Precis of Modern
Tactics_, p. 15, of which I can neither find the original authority
nor do I fully understand the meaning. He is reported to have said
that "there are some who, from some physical or moral peculiarity of
character, form a picture (_tableau_) of everything. No matter what
knowledge, intellect, courage, or good qualities they may have,
these men are unfit to command." It is possible that "tableau"
should be construed rather in the sense of a pictorial composition,
which, like an epigrammatic sentence, may be very complete and
effective, but not altogether true.

There can, however, be no doubt as to the utility of the visualising
faculty when it is duly subordinated to the higher intellectual
operations. A visual image is the most perfect form of mental
representation wherever the shape, position, and relations of
objects in space are concerned. It is of importance in every
handicraft and profession where design is required. The best workmen
are those who visualise the whole of what they propose to do, before
they take a tool in their hands. The village smith