WHY SMOOTHNESS IS BEAUTIFUL.

It is to explain the true cause of visual beauty that I call in the assistance of the other senses.  If it appears that smoothness is a principal cause of pleasure to the touch, taste, smell, and hearing, it will be easily admitted a constituent of visual beauty; especially as we have before shown, that this quality is found almost without exception in all bodies that are by general consent held beautiful.  There can be no doubt that bodies which are rough and angular, rouse and vellicate the organs of feeling, causing a sense of pain, which consists in the violent tension or contraction of the muscular fibres.  On the contrary, the application of smooth bodies relaxes; gentle stroking with a smooth hand allays violent pains and cramps, and relaxes the suffering parts from their unnatural tension; and it has therefore very often no mean effect in removing swellings and obstructions.  The sense of feeling is highly gratified with smooth bodies.  A bed smoothly laid, and soft, that is, where the resistance is every way inconsiderable, is a great luxury, disposing to an universal relaxation, and inducing beyond anything else that species of it called sleep.

SECTION XXI.

SWEETNESS, ITS NATURE.

Nor is it only in the touch that smooth bodies cause positive pleasure by relaxation.  In the smell and taste, we find all things agreeable to them, and which are commonly called sweet, to be of a smooth nature, and that they all evidently tend to relax their respective sensories.  Let us first consider the taste.  Since it is most easy to inquire into the property of liquids, and since all things seem to want a fluid vehicle to make them tasted at all, I intend rather to consider the liquid than the solid parts of our food.  The vehicles of all tastes are water and oil.  And what determines the taste is some salt, which affects variously according to its nature, or its manner of being combined with other things.  Water and oil, simply considered, are capable of giving some pleasure to the taste.  Water, when simple, is insipid, inodorous, colorless, and smooth; it is found, when not cold, to be a great resolver of spasms, and lubricator of the fibres; this power it probably owes to its smoothness.  For as fluidity depends, according to the most general opinion, on the roundness, smoothness, and weak cohesion of the component parts of any body, and as water acts merely as a simple fluid, it follows that the cause of its fluidity is likewise the cause of its relaxing quality, namely, the smoothness and slippery texture of its parts.  The other fluid vehicle of tastes is oil.  This too, when simple, is insipid, inodorous, colorless, and smooth to the touch and taste.  It is smoother than water, and in many cases yet more relaxing.  Oil is in some degree pleasant to the eye, the touch, and the taste, insipid