No man was more practised in this art of the mind than POPE, and even the night was not an unregarded portion of his poetical existence, not less than with LEONARDO DA VINCI, who tells us how often he found the use of recollecting the ideas of what he had considered in the day after he had retired to bed, encompassed by the silence and obscurity of the night.

Sleepless nights are the portion of genius when engaged in its work; the train of reasoning is still pursued; the images of fancy catch a fresh illumination; and even a happy expression shall linger in the ear of him who turns about for the soft composure to which his troubled spirit cannot settle.
[Footnote A: One of the most extraordinary instances of inspiration in dreams is told of Tartini, the Italian musician, whose "Devil's Sonata" is well known to musicians.

He dreamed that the father of evil played this piece to him, and upon waking he put it on paper.

It is a strange wild performance, possessing great originality and vigour .-- ED.] But while with genius so much seems fortuitous, in its great operations the march of the mind appears regular, and requires preparation.

The intellectual faculties are not always co-existent, or do not always act simultaneously.