er and Byron also began at
sixteen. Besides this, we know that the talent for versification, at
least as imitation, is very early in developing.

In mechanical arts children have early a remarkable capacity for
understanding and imitating. At nine, Poncelet bought a watch that was
out of order in order to study it, then took it apart and put it
together correctly. Arago tells that at the same age Fresnel was called
by his comrades a "man of genius," because he had determined by correct
experiments "the length and caliber of children's elder-wood toy cannon
giving the longest range; also, which green or dry woods used in the
manufacture of bows have most strength and lasting power." In general,
the average of mechanical invention is later, and scarcely comes earlier
than that of scientific discovery.

The form of abstract imagination requisite for invention in the sciences
has no great personal value before the twentieth year: there are a
goodly number, however, who have given proof of it before that
age--Pascal, Newton, Leibniz, Gauss, Auguste Comte, etc. Almost all are
mathematicians.

These chronological variations result not from chance, but from
psychological conditions necessary for the development of each form of
imagination. We know that the acquisition of musical sounds is prior to
speech: many children can repeat a scale correctly before they are able
to talk. On the other hand, as dissolution follows evolution in inverse
order,[67] aphasic patients lacking the most common words, can
nevertheless sing. Sound-images are thus organized before all others,
and the creative power when acting in this direction finds very early
material for its use. For the plastic arts a longer apprenticeship is
necessary for the education of the senses and movements. To acquire
manual dexterity one must become skilled in observing form, combinations
of lines and colors, and apt at reproducing them. Poetry and first
attempts at novel-writing presuppose some experience of the passions of
human life and a certain reflection of which the child is incapable.
Invention in the mechanic arts, as in the plastic arts, requires the
education of the senses and movements; and, further, calculation,
rational combination of means, rigorous adaptation to practical
necessities. Lastly, scientific imagination is nothing without a high
development of the capacity for abstraction, which is a matter of slow
growth. Mathematicians are the most precoci