If a stimulus be repeated at uniform intervals of time, the action, whether of our muscles or organs of sense, is produced with still greater facility or energy; because the sensorial power of association, mentioned above, is combined with the sensorial power of irritation; that is in common language, the acquired habit assists the power of the stimulus.
This not only obtains in the annual, lunar, and diurnal catenations of animal motions, as explained in Zoonomia, Sect. XXXVI. which are thus performed with great facility and energy; but in every less circle of actions or ideas, as in the burden of a song, or the reiterations of a dance. To the facility and distinctness, with which we hear sounds at repeated intervals, we owe the pleasure, which we receive from musical time, and from poetic time, as described in Botanic Garden, V. II. Interlude III. And to this the pleasure we receive from the rhimes and alliterations of modern versification; the source of which without this key would be difficult to discover.
There is no variety of notes referable to the gamut in the beating of a drum, yet if it be performed in musical time, it is agreeable to our ears; and therefore this pleasurable sensation must be owing to the repetition of the divisions of the sounds at certain intervals of time, or musical bars. Whether these times or bars are distinguished by a pause, or by an emphasis, or accent, certain it is, that this distinction is perpetually repeated; otherwise the ear could not determine instantly, whether the successions of sound were in common or in triple time.
But besides these little circles of musical time, there are the greater returning periods, and the still more distinct choruses; which, like the rhimes at the end of verses, owe their beauty to repetition; that is, to the facility and distinctness with which we perceive sounds, which we expect to perceive or have perceived before; or in the language of this work, to the greater ease and energy with which our organ is excited by the combined sensorial powers of association and irritation, than by the latter singly.
This kind of pleasure arising from repetition, that is from the facility and distinctness with which we perceive and understand repeated sensations, enters into all the agreeable arts; and when it is carried to excess is termed formality. The art of dancing like that of music depends for a great part of the pleasure, it affords, on repetition; architecture, especially the Grecian, consists of one part being a repetition of another, and hence the beauty of the pyramidal outline in landscape-painting; where one side of the picture may be said in some measure to balance the other. So universally does repetition contribute to our pleasure in the fine arts, that beauty itself has been defined by some writers to consist in a due combination of uniformity and variety: Zoonomia, Vol. I. Sect. XXII. 2. 1.
Where these repetitions of form, and reiterations of colour, are produced in a picture or a natural landscape, in an agreeable quantity, it is termed simplicity, or unity of character; where the repetition principally is seen in the disposition or locality of the divisions, it is called symmetry, proportion, or grouping the separate parts; where this repetition is most conspicuous in the forms of visible objects, it is called regularity or uniformity; and where it affects the colouring principally, the artists call it breadth of colour.
There is nevertheless, an excess of the repetition of the same or similar ideas, which ceases to please, and must therefore be excluded from compositions of Taste in painted landscapes, or in ornamented gardens; which is then called formality, monotony, or insipidity. Why the excitation of ideas should give additional pleasure by the facility and distinctness of their production for a certain time, and then cease to give additional pleasure; 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.