СНАР. V. Of Sight. a person would not be able to distinguish the blush of modesty or glow of sensibility, from the redness caused by intemperance, or morbid inflammation: nor would the delicate fairness, or cadaverous whiteness of a skin make any other impressions respectively upon his feelings, than the same different degrees or modifications of the same tint, seen in other substances. All the fascinating attractions of these charms of the sex owe their influence to sympathy and habit; as being symptoms of mental and bodily perfections, the meaning of which is only known by experience and observation; so that it could neither be felt nor understood by a person, who saw them for the first time. The redness of any morbid inflammation may display a gradation of tint, which, in a pink or a rose, we should think as beautiful as the purple light of love and bloom of young desire; and the cadaverous paleness of death or disease, a degree of whiteness, which, in a piece of marble or alabaster, we should deem to be as pure, as that of the most delicate skin of the fairest damsel of the frigid zone: consequently, the mere visible beauty is in both the same; and the difference consists entirely in mental sympathies, excited by certain internal stimuli, and guided by habit. The African black, when he first beholds an European complexion, thinks both its red and CHAP. V. Of Sight. Were it possible beauty of colour white morbid and unnatural, and of course 28. As light is the sole medium of vision, the effects of visible objects upon the eye must depend, not only upon the quantities reflected from them, and the modes of its reflection or refraction, but, likewise, upon the degree of force with which it acts; and this, as well as the quantity, depends, in a great measure, upon the degrees of proximity between the object and the organ. Hence in proportion as bodies are near, their outlines appear more sharp, their colours more vivid, and their lights and shadows more forcible and distinct; and, in proportion as they recede from us, all these gradually fade away, till at length they entirely vanish. Hence there are visible variations in the eye according to the distance of the object, to which it is directed; which seem to be produced by the greater or smaller degrees of irritation caused by impressions more or less vivid *. CHAP. V. Of Sight. It has been calculated that objects are visible at the distance of 3436 times their diametre, if viewed by eyes perfectly organized, and through the common medium of common daylight equally diffused from the organ to the object: but in proportion as the comparative degree of light is greater upon the object than upon the eye, this power of seeing it at a distance will be extended; and in proportion as it is less, it will be shortened. We can see a burning coal by night at least 100 times as far as we can see the same coal extinct by daylight; and the difference is proportionately great between looking out of an obscure room upon objects in sunshine, and looking from sunshine at objects in an obscure room. The above calculation relates of course to the powers of the human eye; there being many kinds of birds of prey, such as eagles, kites, &c. which manifestly possess them in a much greater extent. CHAP. V. Of Sight. 29. Similar variations are produced, as before observed, by different quantities of light thrown directly upon the eyes; the membrane of the iris contracting with its increase, and dilating with its decrease, in proportion as the irritation is more or less violent. When extended beyond a certain degree, it becomes absolutely painful; and in that case, the eloquent author, already so often cited, by mistaking as usual a power for a sensation, concludes it to be sublime; though if he or any other person had been compelled to expose their eyes to unsufferable light for a few moments, they would have felt how totally void of all sublime ideas their minds would have become, how much soever the power and magnificence of such light, surrounding the throne of Omnipotence, might have exalted or expanded their imaginations, when described in the verses of Milton. 30. Darkness is the entire cessation or absence of light; and, of course, utterly negative, and producing no sensation at all of itself: but, nevertheless, when we go suddenly out of a very strong light into it, the transition, like all other very violent and quick transitions, may be painful to very tender eyes; as there will ensue a sudden change in the internal state of the fibres; which, notwithstanding + Sublime and Beautiful, Part II. f. xiv. et seq. that it be from tension to relaxation, and from irritation to repose, may nevertheless, in the first sensation of it, be, unpleasant to some organs, though I could never feel it so. But to imagine that darkness is painful to the sight, because we sometimes strain our eyelids to such a degree as to produce pain, in the efforts which we make to see in the dark, is one of the most unaccountable fancies that ever arose in the mind of any man: for if darkness be in itself painful, a person with his eyes shut in a dark room must be in an agony; and yet so widely does the practice of mankind differ from the theories of philosophers, that this is the state, in which we all usually go to sleep; and is probably that, in which this great philosopher and statesman slept as well as the meanest of the swinish multitude. It is to darkness, likewise, that men fly for relief, when their eyes, through weakness or inflammation, cannot bear the irritation of light: but I never yet heard of any one, whose eyes were so heterogeneously organized, or so strangely morbid, that they could not bear the effect of darkness, whatever it may be: for as to the uneasiness, which the boy, couched by Cheselden, felt at the first sight of a black object, it arose either from the harshness of its outline, or from its appearing * Part IV. f. xv. &c. CHAP. Of Sight. |