easure; and gradually to give less
pleasure than that, which attends simple exertion of them; is another
curious metaphysical problem, and deserves investigation.

In our waking hours a perpetual voluntary exertion, of which we are
unconscious, attends all our new trains of ideas, whether those of
imagination or of perception; which by comparing them with our former
experience preserves the consistency of the former, by rejecting such
as are incongruous; and adds to the credibility of the latter, by
their analogy to objects of our previous knowledge: and this exertion
is attended with pleasurable sensation. After very frequent repetition
these trains of ideas do not excite the exertion of this intuitive
analogy, and in consequence are not attended with additional pleasure
to that simply of perception; and by continued repetition they at
length lose even the pleasure simply of perception, and thence finally
cease to be excited; whence one cause of the torpor of old age, and of
death, as spoken of in Additional Note, No. VII. 3. of this work.

When there exists in any landscape a certain number and diversity of
forms and colours, or of their combinations or successions, so as to
produce a degree of novelty; and that with a certain repetition, or
arrangement of parts, so as to render them gradually comprehensible or
easily compared with the usual course of nature; if this agreeable
combination of visible objects be on a moderate scale, in respect to
magnitude, and form the principal part of the landscape, it is termed
PICTURESQUE by modern artists; and when such a combination of forms
and colours contains many easy flowing curves and smooth surfaces, the
delightful sentiment of BEAUTY becomes added to the pleasure of the
Picturesque.

If the above agreeable combination of novelty and repetition exists on
a larger scale with more projecting rocks, and deeper dells, and
perhaps with a somewhat greater proportion of novelty than repetition,
the landscape assumes the name of ROMANTIC; and if some of these forms
or combinations are much above the usual magnitude of similar objects,
the more interesting sentiment of SUBLIMITY becomes mixed with the
pleasure of the romantic.

III. _Melody of Colours._

A third source of pleasure arising from the inspection of visible
objects, besides that of simple perception, arises from what may be
termed melody of colours, as certain colours are more agreeable, when
they succeed each o