The folding doors swung on pivots, which were fitted into sockets in the threshold (β, β) and in the lintel. The pivots were of wood, but were provided—at least the lower ones—with a cylindrical cap of iron or bronze, and the socket had a protective lining of the same metal. Both caps and sockets, especially those of bronze, are found in the thresholds in a good state of preservation. It seems strange that ancient builders did not use smaller pivots of solid metal, on which the doors would have turned much more easily; but a conservative tradition in this regard prevailed against innovation.

The fastenings were elaborate. Near the inner edge of each door was a vertical bolt, which shot into a hole in the threshold (γ, γ); there was probably a corresponding bolt at the top, as in the case of large modern doors. Sometimes there was a heavy iron lock, turned with a key, and also an iron bar which was fastened across the crack in such a way as to tie the two folds together. In many houses there are holes in the walls of the fauces, just back of the door, in which at night a strong wooden bar, sera, was placed; hardly less often we find a hole in the floor a few feet back, in which one end of a slanting prop was set, the other end being braced against the middle of the door. These arrangements bring to mind Juvenal's vivid picture of the disturbances and dangers of the streets of Rome at night.

II. The Atrium

An atrium completely covered by a roof was extremely rare. With few exceptions, there was a large rectangular opening over the middle, compluvium, toward which the roof sloped from all sides ([Figs. 114], [118]). In the floor, directly under the compluvium, was a shallow basin, impluvium, into which the rain water fell (h in [Fig. 118]). The impluvium had two outlets. One was connected with the cistern; a round cistern mouth, puteal, ornamented with carving, often stood near the edge of the basin, as in the house of the Tragic Poet ([Fig. 153]). The other outlet led under the floor to the street in front, carrying off the overflow when the cistern was full, and also the water used in cleaning the floor. In the better houses a fountain was often placed in the middle of the impluvium.

Vitruvius (VI. iii. 1 et seq.) mentions five kinds of atriums, the basis of classification being the construction of the roof—Tuscan, tetrastyle, Corinthian, displuviate, and tortoise atriums. The first three are well illustrated at Pompeii.

The Tuscan atrium, supposed by the Romans to have been derived from the Etruscans, was apparently the native Italic form. Two heavy girders were placed across the room, above the ends of the impluvium ([Fig. 117], b). On these, two shorter crossbeams were laid (c), over the sides of the impluvium. The corners of the rectangular frame thus made were connected with the walls at the corners of the atrium by four strong slanting beams ([Figs. 117], [118], e). On these and on the frame were placed the lower ends of the sloping rafters ([Fig. 117], f), carrying the tiles, the arrangement of which can be seen in [Figs. 114], [117], and [118]. This was the most common arrangement of the roof at Pompeii.

Fig. 117.—A Tuscan atrium: plan of the roof.
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