In the last half-century of the Republic, to which belong the earliest Roman poets who describe Nature, the town life, varied by retirement to the Tiburtine or Sabine villa, was universal among the poets and their associates. Some of them had passed their childhood in the rustic life of distant provinces, and the remembrance of that life still lives in their poetry, as in Catullus, and more distinctively in Virgil. The earliest pictures of Nature that occur in any Roman poetry are to be found not in pastoral or idyl, but in the great philosophic poem that expounds an elaborate system of Nature. Lucretius was too earnest a preacher of his Atomic Philosophy to linger over descriptions of scenery for their own sake. Nevertheless, his wearisome expositions of materialistic system are relieved by many a beautiful illustration drawn directly from the Nature which his own eyes had seen, and portrayed with a clearness of outline and a startling vividness, in which, as Professor Sellar has truly said, he is unrivaled in antiquity save by Homer. The rigorous dogmatism of a mechanical philosophy is in him combined with the keenest eye to all the appearances of the outer world, minute as well as vast. Evidently he had lived much in the open air, had been a haunter of all waste places, wild mountain ranges, dripping caves, solitary sea-shores. He had noted all the sights, listened to the sounds and the silences, and observed the ways of the wild creatures that dwell there. His impressions he has stamped in many a noble line, that comes in with delightful freshness to illustrate his prolix argument. His eye was upon the smallest and most sequestered appearances, as the many-colored shells on the shore, and the dripping of water over moss-covered rocks; but still more familiarly did his imagination move with the great elemental movements of Nature, and when the storms and winds were up, he found himself “one among the many there.” According to the philosophy he had adopted, and earnestly propounded, all the most beautiful and mysterious aspects of things were the mere products of dead mechanic forces. But the genius of the poet at times shook itself free from the trammels of his creed, and rose to the contemplation, not of a dead mechanic world, but of one informed by a vast life, which moves through all material things, and makes them instinct with unity. In the language of the philosophers, while consciously he taught only a _Natura naturata_, his imagination and sympathy grasped, in spite of him, a _Natura naturans_. It is impossible that any great poet, however his understanding may be caught in the meshes of mere materialism, can in his hours of inspiration rest contented with that. Assuredly Lucretius did not. Accordingly, we find him here and there breaking out into the earliest utterance of that mystical Pantheistic feeling about the life of Nature, which we shall find reappearing in Virgil, and which has recurred so powerfully in modern poetry.