And, if there be so much art in the choice of fit precepts, there is much more required in the treating of them, that they may fall in after each other by a natural unforced method, and show themselves in the best and most advantageous light. They should all be so finely wrought together in the same piece, that no coarse seam may discover where they join; as, in a curious brede of needle-work, one colour falls away by such just degrees, and another rises so insensibly, that we see the variety, without being able to distinguish the total vanishing of the one from the first appearance of the other. Nor is it sufficient to range and dispose this body of precepts into a clear and easy method, unless they are delivered to us in the most pleasing and agreeable manner: for there are several ways of conveying the same truth to the mind of man; and to chuse the pleasantest of these ways, is that which chiefly distinguishes poetry from prose, and makes Virgil's rules of husbandry pleasanter to read than Varro's. Where the prose-writer tells us plainly what ought to be done, the poet often conceals the precept in a description, and represents his countryman performing the action in which he would instruct his reader. Where the one sets out, as fully and distinctly as he can, all the parts of the truth which he would communicate to us, the other singles out the most pleasing circumstance of this truth, and so conveys the whole in a more diverting manner to the understanding. I shall give one instance, out of a multitude of this nature, that might be found in the Georgics, where the reader may see the different ways Virgil has taken to express the same thing, and how much pleasanter every manner of expression is, than the plain and direct mention of it would have been. It is in the Second Georgic, where he tells us what trees will bear grafting on each other: _Et sæpe alterius ramos impune videmus Vertere in alterius, mutatamque insita mala Ferre pyrum, et prunis lapidosa rubescere corna. --Steriles platani malos gessere valentes: Castaneæ fagus, ornusque incanuit albo Flore pyri; glandemque sues fregere sub ulmis. ----Nec longum tempus; et ingens Exiit ad cælum ramis felicibus arbos; Miraturque novas frondes, et non sua poma._