The Ptolemies, by their love for the sciences, their splendid establishments for promoting intellectual development, and their unwearied endeavors to extend the advantages of commerce, gave an impulse to the study of nature and the knowledge of geography, such as had not existed in any preceding nation. Even before the first Punic war had shaken the power of Carthage, Alexandria had become the greatest emporium of trade and thought in the world. When martial force had laid the broad foundations of empire far down the track of national destinies, Egypt became a province, and all its immensely valuable attainments in science were transferred to the Romans. As the companions of Alexander had become acquainted with the monsoon winds, which render such powerful assistance in voyages between the east coast of Africa and the west coast of Asia, so the Cæsars, in due time and order, were put in possession of means by which they might compass the western shores of Europe. Thus greater portions of the globe have become accessible, the nations have been drawn together more closely, and the sphere of human knowledge has been progressively enlarged. This direction of Greek thought, which was productive of such grand results, and had been so long in a quiet state of preparation, was manifested in the noblest way at the era of transition from Pericles to Augustus. Its extension at the time of the Lagides may be considered as a very important step in the general knowledge of nature ultimately attained.