Whatever may be said of the accuracy of the great geographer of antiquity, it cannot be denied that he was a man of immense research and learning. His work in seventeen books is one of the most valuable that have come down from antiquity, both from the discussions which run through it, and the curious facts which can be found nowhere else. It is scarcely fair to estimate the genius of Strabo by the correctness and extent of his geographical knowledge. All men are comparatively ignorant in science, because science is confessedly a progressive study. The great scientific lights of our day may be insignificant, compared with those who are to arise, if profundity and accuracy of knowledge be made the test. It is the genius of the ancients, their grasp and power of mind, their original labors, which we are to consider. Thus it would seem that among the ancients, in those departments of science which are inductive, there were not sufficient facts, well established, from which to make sound inductions; but in those departments which are deductive, like pure mathematics, and which require great reasoning powers, there were lofty attainments,--which indeed gave the foundation for the achievements of modern science. * * * * * AUTHORITIES. An exceedingly learned work (London, 1862) on the Astronomy of the Ancients, by Sir George Cornewall Lewis, though rather ostentatious in the parade of authorities, and minute on points which are not of much consequence, is worth consulting. Delambre's History of Ancient Astronomy has long been a classic, but is richer in materials for a history than a history itself. There is a valuable essay in the Encyclopaedia Britannica, which refers to a list of special authors. Whewell's History of the Inductive Sciences may also be consulted with profit. Dunglison's History of Medicine is a standard, giving much detailed information, and Leclerc among the French and Speugel among the Germans are esteemed authorities. Strabo's Geography is the most valuable of antiquity; see also Polybius: both of these have been translated and edited for English readers. MATERIAL LIFE OF THE ANCIENTS. MECHANICAL AND USEFUL ARTS. 4000-50 B.C.