Nature , in the common sense, refers to essences unchanged by man; space, the air, the river, the leaf.  Art  is applied to the mixture of his will with the same things, as in a house, a canal, a statue, a picture.

But his operations taken together are so insignificant, a little chipping, baking, patching, and washing, that in an impression so grand as that of the world on the human mind, they do not vary the result.