custom; or from the fitness which some measures have to answer some particular ends of conveniency. Our business therefore is to inquire, whether the parts of those objects, which are found beautiful in the vegetable or animal kingdoms, are constantly so formed according to such certain measures, as may serve to satisfy us that their beauty results from those measures, on the principle of a natural mechanical cause; or from custom; or, in fine, from their fitness for any determinate purposes. I intend to examine this point under each of these heads in their order. But before I proceed further, I hope it will not be thought amiss, if I lay down the rules which governed me in this inquiry, and which have misled me in it, if I have gone astray. 1. If two bodies produce the same or a similar effect on the mind, and on examination they are found to agree in some of their properties, and to differ in others; the common effect is to be attributed to the properties in which they agree, and not to those in which they differ. 2. Not to account for the effect of a natural object from the effect of an artificial object. 3. Not to account for the effect of any natural object from a conclusion of our reason concerning its uses, if a natural cause may be assigned. 4. Not to admit any determinate quantity, or any relation of quantity, as the cause of a certain effect, if the effect is produced by different or opposite measures and relations; or if these measures and relations may exist, and yet the effect may not be produced. These are the rules which I have chiefly followed, whilst I examined into the power of proportion considered as a natural cause; and these, if he thinks them just, I request the reader to carry with him throughout the following discussion; whilst we inquire, in the first place, in what things we find this quality of beauty; next, to see whether in these we can find any assignable proportions in such a manner as ought to convince us that our idea of beauty results from them. We shall consider this pleasing power as it appears in vegetables, in the inferior animals, and in man. Turning our eyes to the vegetable creation, we find nothing there so beautiful as flowers; but flowers are almost of every sort of shape, and of every sort of disposition; they are turned and fashioned into an infinite variety of forms; and from these forms botanists have given them their names, which are almost as various. What proportion do we discover between the stalks and the leaves of flowers, or between the leaves and the pistils? How does the slender stalk of the rose agree with the bulky head under which it bends? but the rose is a beautiful flower; and can we undertake to say that it does not owe a great deal of its beauty even to that disproportion; the rose is a large flower, yet it grows upon a small shrub; the flower of the apple is very small, and grows upon a large tree; yet the rose and the apple blossom are both