XV
Darkness Terrible In Its Own Nature Perhaps it may appear on inquiry that blackness and darkness are in some degree painful by their natural operation,independent of any associations whatsoever.I must observe,that the ideas of darkness and blackness are much the same;and they differ only in this,that blackness is a more confined idea.Mr.Cheselden has given us a very curious story of a boy,who had been born blind,and continued so until he was thirteen or fourteen years old;he was then couched for a cataract,by which operation he received his sight.
Among many remarkable particulars that attended his first perceptions and judgments on visual objects,it gave him great uneasiness;and that some time after,upon accidentally seeing a negro woman,he was struck with great horror at the sight.The horror,in this case,can scarcely be supposed to arise from any association.The boy appears by the account to have been particularly observing and sensible for one of his age;and therefore it is probable,if the great uneasiness he felt at the first sight of black had arisen from its connexion with any other disagreeable ideas,he would have observed and mentioned it.For an idea,disagreeable only by association,has the cause of its ill effect on the passions evident enough at the first impression;in ordinary cases,it is indeed frequently lost;but this is,because the original association was made very early,and the consequent impression repeated often.In our instance,there was no time for such a habit;and there is no reason to think that the ill effects of black on his imagination were more owing to its connexion with any disagreeable ideas,than that the good effects of more cheerful colours were derived from their connexion with pleasuring ones.They had both probably their effects from their natural operation.
XVI
Why Darkness Is Terrible It may be worth while to examine how darkness can operate in such a manner as to cause pain.It is observable,that still as we recede from the light,nature has so contrived it,that the pupil is enlarged by the retiring of the iris,in proportion to our recess.Now,instead of declining from it but a little,suppose that we withdraw entirely from the light;it is reasonable to think,that the contraction of the radial fibres of the iris is proportionably greater;and that this part may by great darkness come to be so contracted as to strain the nerves that compose it beyond their natural tone;and by this means to produce a painful sensation.Such a tension it seems there certainly is,whilst we are involved in darkness;for in such a state,whilst the eye remains open,there is a continual nisus to receive light;this is manifest from the flashes and luminous appearances which often seem in these circumstances to play before it;and which can be nothing but the effect of spasms,produced by its own efforts in pursuit of its object:several other strong impulses will produce the idea of light in the eye,besides the substance of light itself,as we experience on many occasions.Some,who allow darkness to be a cause of the sublime,would infer,from the dilatation of the pupil,that a relaxation may be productive of the sublime,as well as a convulsion:but they do not,I believe,consider that although the circular ring of the iris be in some sense a sphincter,which may possibly be dilated by a simple relaxation,yet in one respect it differs from most of the other sphincters of the body,that it is furnished with antagonist muscles,which are the radial fibres of the iris:no sooner does the circular muscle begin to relax,than these fibres,wanting their counterpoise,are forcibly drawn back,and open the pupil to a considerable wideness.
But though we were not apprized of this,I believe any one will find,if he opens his eyes and makes an effort to see in a dark place,that a very perceivable pain ensues.And I have heard some ladies remark,that after having worked a long time upon a ground of black,their eyes were so pained and weakened,they could hardly see.It may perhaps be objected to this theory of the mechanical effect of darkness,that the ill effects of darkness or blackness seem rather mental than corporeal:and I own it is true,that they do so;and so do all those that depend on the affections of the finer parts of our system.The ill effects of bad weather appear often no otherwise,than in a melancholy and dejection of spirits;though without doubt,in this case,the bodily organs suffer first,and the mind through these organs.
