The science chiefly cultivated at this period was rhetoric, which appears to have differed considerably from what now passes under the same name. The object of it was not so much justness of sentiment and propriety of expression, as the art of declaiming, or speaking copiously upon any subject. It is mentioned by Varro as the reverse of logic; and they are distinguished from each other by a simile, that the former resembles the palm of the hand expanded, and the latter, contracted into the fist. It is observable that logic, though a part of education in modern times, seems not to have been cultivated amongst the Romans. Perhaps they were apprehensive, lest a science which concentered the force of argument, might obstruct the cultivation of that which was meant to dilate it. Astronomy was long before known in the eastern nations; but there is reason to believe, from a passage in Virgil [269], that it was little cultivated by the Romans; and it is certain, that in the reformation of the calendar, Julius Caesar was chiefly indebted to the scientific knowledge of (158) Sosigenes, a mathematician of Alexandria. The laws of the solar system were still but imperfectly known; the popular belief, that the sun moved round the earth, was universally maintained, and continued until the sixteenth century, when the contrary was proved by Copernicus. There existed many celebrated tracts on mathematics; and several of the mechanical powers, particularly that of the lever, were cultivated with success. The more necessary and useful rules of arithmetic were generally known. The use of the load-stone not being as yet discovered, navigation was conducted in the day-time by the sun, and in the night, by the observation of certain stars. Geography was cultivated during the present period by Strabo and Mela. In natural philosophy little progress was made; but a strong desire of its improvement was entertained, particularly by Virgil. Human anatomy being not yet introduced, physiology was imperfect. Chemistry, as a science, was utterly unknown. In medicine, the writings of Hippocrates, and other Greek physicians, were in general the standard of practice; but the Materia Medica contained few remedies of approved quality, and abounded with useless substances, as well as with many which stood upon no other foundation than the whimsical notions of those who first introduced them. Architecture flourished, through the elegant taste of Vitruvius, and the patronage of the emperor. Painting, statuary, and music, were cultivated, but not with that degree of perfection which they had obtained in the Grecian states. The musical instruments of this period were the flute and the lyre, to which may be added the sistrum, lately imported from Egypt. But the chief glory of the period is its literature, of which we proceed to give some account.