Modern Rome is about thirteen miles in circuit, and is divided by the Tiber into two parts. In 1830, Rome contained 144,542 inhabitants, 35,900 houses, 346 churches, 30 monasteries, and upwards of 120 palaces. The view of the majestic ruins; the solemn grandeur of the churches and palaces; the recollections of the past; the religious customs; the magic and almost melancholy tranquillity which pervades the city; the enjoyment of the endless treasures of art--all conspire to raise the mind of the traveler to a high state of excitement. The churches, palaces, villas, squares, streets, fountains, aqueducts, antiquities, ruins--in short, everything proclaims the ancient majesty and the present greatness of Rome. Almost every church, palace, and villa is a treasury of art. Among the churches, St. Peter's is the most conspicuous, and is, perhaps, the most beautiful building in the world. Bramante began it; Sangallo and Peruzzi succeeded him; but Michael Angelo, who erected its immense dome, which is four hundred and fifty feet high to the top of the cross, designed the greatest part. Many other architects were often employed upon it; Maderno finished the front and the two towers. The erection of this edifice, from 1506 to 1614, cost 45,000,000 Roman crowns. Before we arrive at this grand temple, the eye is attracted by the beautiful square in front of it, surrounded by a magnificent colonnade by Bernini, and ornamented by an Egyptian obelisk, together with two splendid fountains. Upon entering the vestibule, Giotto's mosaic, la Navicella, is seen. Under the portico, opposite the great door, is Bernini's great bas relief representing Christ commanding Peter to feed his sheep; and at the ends of the portico are the equestrian statues of Constantine by Bernini, and of Charlemagne by Cornachini. The union of these masterpieces has an indescribable effect. The harmony and proportion which prevail in the interior of this august temple are such, that, immense as it is, the eye distinguishes all the parts without confusion or difficulty. When each object is minutely examined, we are astonished at its magnitude, so much more considerable than appears at first sight. The immense canopy of the high altar, supported by four bronze pillars of 120 feet in height, particularly attracts the attention. The dome is the boldest work of modern architecture. The cross thereon is 450 feet above the pavement. The lantern affords the most beautiful prospect of the city and the surrounding country. The splendid mosaics, tombs, paintings, frescos, works in marble, gilded bronze and stucco, the new sacristy--a beautiful piece of architecture, but not in unison with the rest--deserve separate consideration. The two most beautiful churches in Rome next to St. Peter's are the St. John's of the Lateran, and the Santa Maria Maggiore. The former, built by Constantine the Great, is the parochial church of the pope; it therefore takes precedence of all others, and is called