in a
harmonious and helpful way, with the new central thought.

[Illustration: FIG. 1.]

Sec. 17. The kind of mental chemistry by which the dream summons and
associates its materials, I have already endeavored, not to explain, for
it is utterly inexplicable, but to illustrate, by a well-ascertained
though equally inexplicable fact in common chemistry. That illustration
(Sec. 8. of chapter on Imaginative Association, Vol. II.) I see more and
more ground to think correct. How far I could show that it held with all
great inventors, I know not, but with all those whom I have carefully
studied (Dante, Scott, Turner, and Tintoret) it seems to me to hold
absolutely; their imagination consisting, not in a voluntary production
of new images, but an involuntary remembrance, exactly at the right
moment, of something they had actually seen.

Imagine all that any of these men had seen or heard in the whole course
of their lives, laid up accurately in their memories as in vast
storehouses, extending, with the poets, even to the slightest
intonations of syllables heard in the beginning of their lives, and,
with the painters, down to the minute folds of drapery, and shapes of
loaves or stones; and over all this unindexed and immeasurable mass of
treasure, the imagination brooding and wandering, but dream-gifted, so
as to summon at any moment exactly such groups of ideas as shall justly
fit each other: this I conceive to be the real nature of the imaginative
mind, and this, I believe, it would be oftener explained to us as
being, by the men themselves who possess it, but that they have no idea
what the state of other persons' minds is in comparison; they suppose
every one remembers all that he has seen in the same way, and do not
understand how it happens that they alone can produce good drawings or
great thoughts.

[Illustration: Turner. T. Boys.
22. Turner's Earliest "Nottingham."]

Sec. 18. Whether this be the case with all inventors or not, it was
assuredly the case with Turner to such an extent that he seems never to
have lost, or cared to disturb, the impression made upon him by any
scene,--even in his earliest youth. He never seems to have gone back to
a place to look at it again, but, as he gained power, to have painted
and repainted it as first seen, associating with it certain new thoughts
or new knowledge, but never shaking the central pillar of the old image.
Several instances of this