Another class of buildings--the basilicæ, exchanges or law courts, are highly interesting from the fact that they were afterward converted into Christian churches. One such edifice was always placed in the forum for the convenience of traders. It was generally of oblong shape, the length being from two to three times greater than the breadth. The earlier edifices of the kind were mere peristyles, or open spaces inclosed by columns, but subsequently the open space was defended by walls--the columns still remaining for ornament. Small private chambers were cut off from one end, for the use of the law officers and merchants; the main area was divided into a nave and two side-aisles. At one extremity of the central nave was placed the tribunal of the judge, which stood within the oblong area so long as the original use of the building merely as a law-court continued; but afterward, when the same edifice was used as an exchange, a semi-circular space was thrown out at one end, and the tribunal placed within this, in order that the seat of justice might not be disturbed by the noise of traffic. The advocates and jurors occupied the space within the semi-circle, while persons interested in the cause were accommodated with side-seats. The columns of the side-aisles supported a gallery, from which rose other columns sustaining a roof usually flat in the centre, and arched down to the supports so as to resemble the shell of the tortoise. It may, perhaps, seem strange, that in our notice of so many ancient buildings we have not once alluded to temples. The reason for this course is, that no description could be given of such structures without necessitating an account of orders, styles, and proportion, into which our subject does not strictly enter. But the peculiar use of marble in constructing the roofs of temples may be well alluded to in this place. Slabs of this material were employed and fixed, much in the same manner as earthen tiles; descending in parallel rows from the ridge of the roof to the eaves. Bronze, afterward gilt, was also used for the same purpose. The Greek and Roman towns were generally irregular in plan; their streets narrow and mean, even in Rome, till the great fire in Nero’s reign; after which the city was rebuilt with great regularity. The increasing value of land led to the erection of many-storied houses in the main streets; but the houses of the wealthy were always chiefly composed of ground-floor apartments, wherever space permitted. This subject, and the house-carpentry generally of the ancients, is involved in some obscurity. VIII. _Traveling._