independently of the will,
and their shape and position, at all events in the mental field of
view, is nearly invariable. They have other points in common to
which I shall shortly draw attention, but first I will endeavour to
remove all doubt as to the authenticity and trustworthiness of these
statements.

I see no "Form" myself, and first ascertained that such a thing
existed through a letter from Mr. G. Bidder, Q.C., in which he
described his own case as a very curious peculiarity. I was at the
time making inquiries about the strength of the visualising faculty
in different persons, and among the numerous replies that reached me
I soon collected ten or twelve other cases in which the writers
spoke of their seeing numerals in definite forms. Though the
information came from independent sources, the expressions used were
so closely alike that they strongly corroborated one another. Of
course I eagerly followed up the inquiry, and when I had collected
enough material to justify publication, I wrote an account which
appeared in _Nature_ on 15th January 1880, with several illustrations.
This has led to a wide correspondence and to a much-increased store
of information, which enables me to arrive at the following
conclusions. The answers I received whenever I have pushed my
questions, have been straightforward and precise. I have not
unfrequently procured a second sketch of the Form even after more
than two years' interval, and found it to agree closely with the
first one. I have also questioned many of my own friends in general
terms as to whether they visualise numbers in any particular way.
The large majority are unable to do so. But every now and then I
meet with persons who possess the faculty, and I have become
familiar with the quick look of intelligence with which they receive
my question. It is as though some chord had been struck which had
not been struck before, and the verbal answers they give me are
precisely of the same type as those written ones of which I have now
so many. I cannot doubt of the authenticity of independent statements
which closely confirm one another, nor of the general accuracy of
the accompanying sketches, because I find now that my collection is
large enough for classification, that they might be arranged in an
approximately continuous series. I am often told that the
peculiarity is common to the speaker and to some near relative, and
that they had found such to be the case by accident.