The designs commence, _on the left side_, with the triumphal entrance of Trajan by the Porta Capena, after the first Dacian war; then, secondly, commemorate his services in carrying the Appian Way through the Pontine Marshes; thirdly, founding an asylum for orphan children; fourthly, his relations with Parthamasiris, king of Armenia. _On the opposite side_, dedication of the aqueduct built by Trajan (_seen on the left_); secondly, audience with the Dacian king Decebalus, whose hired assassins are brought before him; thirdly, with a representation of the emperor haranguing his soldiers; and, fourthly, the emperor offering the _suovetaurilia_ sacrifice of a boar, ram, and bull. Corresponding with these reliefs, two medallions, representing the private life of the emperor in simple and graceful compositions, are introduced over each of the side arches. The first represents his starting for the chase; the second, a sacrifice to Silvanus, the patron of silvan sports; the third displays the emperor on horseback at a bear-hunt; and the fourth a thank-offering to the goddess of hunting. On the side facing the Colosseum, a bear-hunt, a sacrifice to Apollo, a group contemplating a dead lion, and lastly a consultation of an oracle. Most of these refer to Trajan; we think some refer to Hadrian, because on one of them Antinoüs is represented. On the inside of the arch is a battle-piece, assigned to Constantine by the inscriptions, "To the founder of peace," "To the deliverer of the city." They are older than his time. Over the side arches are some narrow reliefs referring to Constantine, one of which is peculiarly interesting, as it represents that emperor addressing the people from the Rostra ad Palmam, with some of the principal monuments in the Forum in the background. THE COLOSSEUM. "A noble wreck in ruinous perfection."--BYRON.