§209. Of the rooms facing the street it will be noticed that one, lightly shaded in the plan, is connected with the _ātrium_; it was probably used for some business conducted by Pansa himself (§193, end), possibly with a slave (§144) or a freedman (§175) in immediate charge of it. Of the others the suites on the east side (A, B) seem to have been rented out as living apartments. The others were shops and stores. The four connected rooms on the west, near the front, seem to have been a large bakery; the room marked C was the salesroom, with a large room opening off of it containing three stone mills, troughs for kneading the dough, a water tap with sink, and a recessed oven. The uses of the others are uncertain. The section plan (Fig. 56) represents the appearance of the house if all were cut away on one side of a line drawn from front to rear through the middle of the house. It is, of course, largely conjectural, but gives a clear idea of the general way in which the division walls and roof must have been arranged. [Illustration: FIGURE 57. WALL OF ROMULUS] §210. The Walls.--The materials of which the wall (_pariēs_) was composed varied with the time, the place, and the cost of transportation. Stone and unburned bricks (_laterēs crūdī_) were the earliest materials used in Italy, as almost everywhere else, timber being employed for merely temporary structures, as in the addition (§190) from which the _tablīnum_ developed. For private houses in very early times and for public buildings in all times, walls of dressed stone (_opus quadrātum_) were laid in regular courses, precisely as in modern times (Fig. 57). Over the wall was spread a coating of fine marble stucco for decorative purposes, which gave it a finish of dazzling white. For less pretentious houses, not for public buildings, the sun-dried bricks were largely used up to about the beginning of the first century B.C. These, too, were covered with the stucco, for protection against the weather as well as for decoration, but even the hard stucco has not preserved walls of this perishable material to our times. In classical times a new material had come into use, better than either brick or stone, cheaper, more durable, more easily worked and transported, which was employed almost exclusively for private houses, and very generally for public buildings. Walls constructed in the new way (_opus caementīcium_) are variously called "rubble-work" or "concrete" in our books of reference, but neither term is quite descriptive; the _opus caementīcium_ was not laid in courses, as is our rubble-work, while on the other hand larger stones were used in it than in the concrete of which walls for buildings are now constructed. [Illustration: FIGURE 58. METHOD OF CASTING CONCRETE WALLS]