The study of archaeology, both on its linguistic and material sides, was carried on in the Augustan age with great vigour, though no single name is comparable to that of Varro for extent and variety of research. One of the most eminent and copious writers on these subjects was Gaius Julius Hyginus, a Spanish freed man of Augustus, who made him principal keeper of the Palatine library. He was a pupil of the most learned Greek grammarian of the age, Cornelius Alexander Polyhistor, and an intimate acquaintance of Ovid. Of his voluminous works on geography, history, astrology, agriculture, and poetry, all are lost but two treatises on mythology, which in their present form are of a much later date, and are at best only abridged and corrupted versions, if (as many modern critics are inclined to think) they are not wholly the work of some author of the second or third century. Hyginus was also one of the earliest commentators on Virgil; he possessed among his treasures a manuscript of the _Georgics,_ which came from Virgil's own house, though it was not actually written by his hand; and many of his annotations and criticisms on the _Aeneid_ are preserved by Aulus Gellius and later commentators. A little later, in the reigns of Tiberius and Claudius, Virgilian criticism was carried on by Quintus Remmius Palaemon of Vicenza, the most fashionable teacher in the capital, and the author of a famous Latin grammar on which all subsequent ones were more or less based. Perhaps the most distinguished of Augustan scholars was another equally celebrated teacher, Marcus Verrius Flaccus, who was chosen by Augustus as tutor for his two grandsons, and thenceforward held his school in the imperial residence on the Palatine. His lexicon, entitled _De Verborum Significatu_, was a rich treasury of antiquarian research: such parts of it as survive in the abridgments made from it in the second and eighth centuries, by Sextus Pompeius Festus and Paulus Diaconus, are still among our most valuable sources for the study of early Latin language and institutions. The more practical side of science in the same period was ably represented by Aulus Cornelius Celsus, the compiler of an encyclopedia which included comprehensive treatises not only on oratory, jurisprudence, and philosophy, but on the arts of war, agriculture, and medicine. The eight books dealing with this last subject are the only part of the work that has been preserved. This treatise, which is written in a pure, simple, and elegant Latin, became a standard work. It was one of the earliest books printed in the fifteenth century, and remained a text-book for medical students till within living memory. Medical science had then reached, in the hands of its leading professors, a greater perfection than it regained till the eighteenth century. Celsus, though not, so far as is known, the author of any important discovery or improvement, had fully mastered a system which even then was highly