For the better carrying on this remarkable analogy of the senses, we may here call sweetness the beautiful of the taste.
SECTION XXIII.
VARIATION, WHY BEAUTIFUL.
Another principal property of beautiful objects is, that the line of their parts is continually varying its direction; but it varies it by a very insensible deviation; it never varies it so quickly as to surprise, or by the sharpness of its angle to cause any twitching or convulsion of the optic nerve.

Nothing long continued in the same manner, nothing very suddenly varied, can be beautiful; because both are opposite to that agreeable relaxation which is the characteristic effect of beauty.

It is thus in all the senses.

A motion in a right line is that manner of moving, next to a very gentle descent, in which we meet the least resistance; yet it is not that manner of moving, which next to a descent, wearies us the least.

Rest certainly tends to relax: yet there is a species of motion which relaxes more than rest; a gentle oscillatory motion, a rising and falling.