general character of roof fall, here and wherever the angle of emergence is steep.
Descending still to the level of the plain, but not far from the hill of Polla, I found the most instructive examples.
The Photogs. Nos. 173 and 174, are views of an isolated sluice-house, that stands upon the east or left bank of the Calore, and was intended for use in relation to irrigation works, connecting the river channel with an artificial one at certain seasons.
In No. 173 the east side and north end of this structure are shown, and in No. 174 the west side and south end. The building is quite modern, constructed of good rubble masonry, with cut limestone quoins and jambs, flat window arches, and stone cornice over entablature. It is about 30 feet high above the soffit of the sluice arch, 30 feet wide north and south, and about 20 feet wide east and west, the walls 2 feet 6 inches thick. The building is exactly cardinal, its longer axis N. and S. Referring to No. 173, heavy inclined fissures will be seen running from both quoins, and meeting near the centre at top. The wall above the window arch is dislocated, and the voussoirs are thrown downwards, by a force emergent from the north, and nearly parallel with the fissure . Several minor fissures, which do not show in the Photog., existed through the arch joints near , at 45° and 55° from the springing (or horizon), and in nearly the same direction, diagonally through the opposite or southern pier face.
The north end wall (to the right in Photog.) is scarcely fissured at all. The whole of the blocks of stone of the cornice at the north end, have been thrown from off the
