At dead of night imperial reason sleeps,
And fancy with her train, her revels keeps;
Then airy phantoms a mix'd scene display,
Of what we heard, or saw, or wish'd by day;
For memory those images retains
Which passion form'd, and still the strongest reigns.
Huntsmen renew the chase they lately run,
And generals fight again their battles won.
Spectres and fairies haunt the murderer's dreams;
Grants and disgraces are the courtier's themes.
The miser spies a thief, or a new hoard;
The cit's a knight; the sycophant a lord,
Thus fancy's in the wild distraction lost,
With what we most abhor, or covet most.
Honours and state before this phantom fall;
For sleep, like death, its image, equals all.

Chaucer in his tale of the Cock and Fox, has a fine description, thus versified by Dryden:—

Dreams are but interludes which fancy makes:
When monarch reason sleeps, this mimic wakes;
Compounds a medley of disjointed things,
A court of coblers and a mob of kings:
Light fumes are merry, grosser fumes are sad:
Both are the reasonable soul run mad;
And many monstrous forms in sleep we see,
That neither were, or are, or e'er can be.
Sometimes forgotten things, long cast behind,
Rush forward in the brain, and come to mind.
The nurse's legends are for truth received,
And the man dreams but what the boy believed,
Sometimes we but rehearse a former play,
The night restores our actions done by day;
As hounds in sleep will open for their prey.
In short, the farce of dreams is of a piece
In chimeras all; and more absurd or less.

Shakspeare again:—

I talk of dreams,
Which are the children of an idle brain,
Begot of nothing but vain phantasy,
Which is as thin of substance as the air,
And more inconsistant than the wind.

Nor must Milton be omitted—

In the soul
Are many lesser faculties, that serve
Reason as chief; among these Fancy next
Her office holds; of all external things,
Which the five watchful senses represent,
She forms imaginations, airy shapes,
Which reason joining, or disjoining, frames,
And all that we affirm, or what deny, or call
Our knowledge or opinion; then retires
Into her private cell, when nature rests.
Oft in her absence mimic fancy wakes,
To imitate her; but misjoining shapes,
Wild works produces oft, but most in dreams
Ill matching words or deeds, long past or tale.

PRINCIPAL PHENOMENA IN DREAMING.

From these practical descriptions let us proceed to take a view of the principal phenomena in dreaming. And first, Mr. Locke's beautiful modes of which will greatly illustrate the preceding observations.

"When the mind," says Locke, "turns its view inward upon itself, and contemplates its own actions, thinking is the first that occurs. In it the mind observes a great variety of modifications, and from thence receives distinct ideas. Thus the perception, which actually accompanies, and is annexed to any impression on the body, made by an external object, being distinct from all other modifications of thinking, furnishes the mind with a distinct idea which we call sensation; which is, as it were, the actual entrance of an idea into the understanding by the senses.