but to what they were when Alexandria was the capital of the country,-- what it was under the Roman domination. [Sidenote: Extent and population of Alexandria.] [Sidenote: Library.] [Sidenote: Public buildings.] [Sidenote: Commerce.] The ground-plan of this great city was traced by Alexander himself, but it was not completed until the reign of Ptolemy Philadelphus. It continued to receive embellishments from nearly every monarch of the Lagian line. Its circumference was about fifteen miles; the streets were regular, and crossed one another at right angles, and were wide enough to admit both carriages and foot passengers. The harbor was large enough to admit the largest fleet ever constructed; its walls and gates were constructed with all the skill and strength known to antiquity; its population numbered six hundred thousand, and all nations were represented in its crowded streets. The wealth of the city may be inferred from the fact that in one year 6250 talents, or more than 6,000,000 dollars, were paid to the public treasury for port dues. The library was the largest in the world, and numbered over seven hundred thousand volumes, and this was connected with a museum, a menagerie, a botanical garden, and various halls for lectures, altogether forming the most famous university in the empire. The inhabitants were chiefly Greek, and had all their cultivated tastes and mercantile thrift. In a commercial point of view it was the most important in the empire, and its ships whitened every sea. Alexandria was of remarkable beauty, and was called by Ammianus _Vertex omnium civitatum_. Its dry atmosphere preserved for centuries the sharp outlines and gay colors of its buildings, some of which were remarkably imposing. The Mausoleum of the Ptolemies, the High Court of justice, the Stadium, the Gymnasium, the Palaestra, the Amphitheatre, and the Temple of the Caesars, all called out the admiration of travelers. The Emporium far surpassed the quays of the Tiber. But the most imposing structure was the Exchange, to which, for eight hundred years, all the nations sent their representatives. It was commerce which made Alexandria so rich and beautiful, for which it was more distinguished than both Tyre and Carthage. Unlike most commercial cities, it was intellectual, and its schools of poetry, mathematics, medicine, philosophy, and theology were more renowned than even those of Athens during the third and fourth centuries. For wealth, population, intelligence, and art, it was the second city of the world. It would be a great capital in these times. [Sidenote: Power of the empire seated in the western provinces.]