Here, we see, the poet considered all the effects of this union between trees of different kinds, and took notice of that effect which had the most surprise, and by consequence the most delight in it, to express the capacity that was in them of being thus united. This way of writing is every where much in use among the poets, and is particularly practised by Virgil, who loves to suggest a truth indirectly, and, without giving us a full and open view of it, to let us see just so much as will naturally lead the imagination into all the parts that lie concealed. This is wonderfully diverting to the understanding, thus to receive a precept, that enters, as it were, through a by-way, and to apprehend an idea that draws a whole train after it. For here the mind, which is always delighted with its own discoveries, only takes the hint from the poet, and seems to work out the rest by the strength of her own faculties. But, since the inculcating precept upon precept will at length prove tiresome to the reader, if he meets with no entertainment,--the poet must take care not to encumber his poem with too much business, but sometimes to relieve the subject with a moral reflection, or let it rest a while for the sake of a pleasant and pertinent digression. Nor is it sufficient to run out into beautiful and diverting digressions, (as it is generally thought,) unless they are brought in aptly, and are something of a piece with the main design of the Georgic: for they ought to have a remote alliance at least to the subject, that so the whole poem may be more uniform and agreeable in all its parts. We should never quite lose sight of the country, though we are sometimes entertained with a distant prospect of it. Of this nature are Virgil's descriptions of the original of agriculture, of the fruitfulness of Italy, of a country life, and the like, which are not brought in by force, but naturally rise out of the principal argument and design of the poem. I know no one digression in the Georgics that may seem to contradict this observation, besides that in the latter end of the first book, where the poet launches out into a discourse of the battle of Pharsalia, and the actions of Augustus: but it is worth while to consider how admirably he has turned the course of his narration into its proper channel, and made his husbandman concerned even in what relates to the battle, in those inimitable lines: _Scilicet et tempus veniet, cum finibus illis Agricola, incurvo terram molitus aratro, Exesa inveniet scabrâ rubigine pila, Aut gravibus rastris galeas pulsabit inanes, Grandiaque effossis mirabitur ossa sepulcris._ And afterwards, speaking of Augustus's actions, he still remembers, that agriculture ought to be some way hinted at throughout the whole poem: ----_Non ullus aratro Dignus honos: squalent abductis arva colonis; Et curvæ rigidum falces conflantur in ensem._