242 Life and Letters of Francis Galton
to them. Much of the data has never been published ; Galton continued to collect for a revised edition of the Inquiries which he never issued. In particular there is a docket dealing with heredity in number forms, and he accumulated much evidence to show-not that the particular number forms-but that the tendency to visualise numbers runs in families. Before he discussed the matter in his Inquiries into Human Faculty, he published two memoirs on the topic. The first, entitled "Visualised Numerals," appeared in Nature Jan. 15, 1880'. And the second, with the same title, in the Journal of the Anthropological Institute, being a paper read on March 9, 18802. At this time Galton had collected eighty such number forms and he found that about one person in thirty adult males and one in fifteen adult females possessed a number form. Among children they appeared to be more frequent, but were less fixed and distinct and tended to fade away with age. The `form,' Galton considered, was of an older date than that at which a child began to learn to read, and represented his mental processes at a time of which no other record remains (J. A. 1. p. 93 and especially Nature, p. 495). The `forms,' he held, were the most remarkable existing instances of what has been termed "topical memory," the establishment of an association between position and the thing to be remembered; a link emphasised by teachers of mnemonics when they advise speakers to associate mentally the corners of a room with the different topics of a speech they are about to deliver. Discussing the relative frequency of number forms in the two sexes Galton writes
"I have been astonished to find how superior women usually are to men in the vividness of their mental imagery and in their powers of introspection I find the attention of women, especially women of ability, to be instantly aroused by these inquiries. They eagerly
and carefully address themselves to consider their modes of thought, they put pertinent questions, they suggest tests, they express themselves in well-weighed language and with happy turns of expression, and they are evidently masters of the art of introspection. I do not find any peculiar tendency to exaggeration in this matter either among women or men; the only difference I have observed between them is that the former usually show an unexpected amount of intelligence, while many of the latter are unexpectedly obtuse.- The mental difference between the two sexes seems wider in the vividness of their mental imagery and the power of introspecting it than in respect to any other combination of mental faculties of which I can
think." (Nature, p. 252.)
The paper read before the Anthropological Institute was not only fuller than that in Nature, but was of special interest because Mr George Bidder, Colonel-Yule, the Rev. G. Henslow, Mr (now Sir) Arthur Schuster, and others each described their own number forms. It would seem that these gentlemen were unaware, until Francis Galton began his inquiry, that there was anything unusual in the possession of a number form. This experience I also have had not infrequently, when I have found a person with a number form; he seemed to suppose everybody had a number form, and to be rather incredulous when I asserted that this was not so. Galton himself, it is of interest to note, did not visualise numerals. He writes
1 Vol. xxi, pp. 252-3, 323, 494-5. 2 Vol. x, pp. 85-102. The copies of both these memoirs in the Galtoniana contain the names of the various contributors of number forms.