ours, combinations, or successions of
them. Whence the beautiful, sublime, romantic, melancholic, and other
emotions, which have not acquired names to express them. We may add,
that all these four sources of pleasure from perceptions are equally
applicable to those of sounds as of sights.

I. _Novelty or infrequency of visible objects._

The first circumstance, which suggests an additional pleasure in the
contemplation of visible objects, besides that of simple perception,
arises from their novelty or infrequency; that is from the unusual
combinations or successions of their forms or colours. From this
source is derived the perpetual cheerfulness of youth, and the want of
it is liable to add a gloom to the countenance of age. It is this
which produces variety in landscape compared with the common course of
nature, an intricacy which incites investigation, and a curiosity
which leads to explore the works of nature. Those who travel into
foreign regions instigated by curiosity, or who examine and unfold the
intricacies of sciences at home, are led by novelty; which not only
supplies ornament to beauty or to grandeur, but adds agreeable
surprise to the point of the epigram, and to the double meaning of the
pun, and is courted alike by poets and philosophers.

It should be here premised, that the word Novelty, as used in these
pages, admits of degrees or quantities, some objects, or the ideas
excited by them, possessing more or less novelty, as they are more or
less unusual. Which the reader will please to attend to, as we have
used the word Infrequency of objects, or of the ideas excited by them,
to express the degrees or quantities of their novelty.

The source, from which is derived the pleasure of novelty, is a
metaphysical inquiry of great curiosity, and will on that account
excuse my here introducing it. In our waking hours whenever an idea
occurs, which is incongruous to our former experience, we instantly
dissever the train of imagination by the power of volition; and
compare the incongruous idea with our previous knowledge of nature,
and reject it. This operation of the mind has not yet acquired a
specific name, though it is exerted every minute of our waking hours,
unless it may be termed INTUITIVE ANALOGY. It is an act of reasoning
of which we are unconscious except by its effects in preserving the
congruity of our ideas; Zoonomia, Vol. I. Sect. XVII. 5. 7.

In our sleep as the power of volition is suspend