Some notes made at Bath further explain the interesting methods of building vaults with box voussoirs. There are several such voussoirs in the ruins of the Great Bath, 12 in. to 13 in. deep by 6 in. and 6½ in.; 6¾ in. and 7½ in.; 8¼ in. and 10 in.; 8 in. and 11 in. at the top and bottom. Fig. 9 is a sketch of the third; it is scored on the face. The notches cut in the sides take the place of the holes in the London examples, and doubtless were for the mortar to get a better key; Fig. 10 is from a vault of this construction which was further strengthened by a series of curved tiles set in the outer concrete mass, which was 6 in. thick; Fig. 11 shows the ridge of such a vault—this may be an imagination of my own. One of the fragments showed six or eight flat tiles set longitudinally crossing the lines of the box-tiles (Fig. 12). The ridge termination (Fig. 16) is also from Bath. [Illustration: FIG. 9. ] [Illustration: FIG. 10. ] Some large voussoir box-tiles from Gaul are shown in the British Museum, No. 394, in the section of Greek and Roman life. [Illustration: FIG. 11. ] [Illustration: FIG. 12. ] Well-constructed arched sewers have been found in the City (see _Victoria County History_). Many socketed water-pipes are in our museums. Such pipes were occasionally used in Rome as down-pipes, and we might do worse than revert to the custom and get rid of the iron rust nuisance. In the British Museum there are some larger socketed pipes with small holes cut in them along a line. These must, I think, have been for draining surface water, for which purpose flue tiles were also used. Larger sewers were of brick or stone. _Carpentry._—In mediæval days the carpenter was the chief house builder, and much timber would have been used in Roman London. In 1901-2 remains of piling was found in the bed of the Walbrook at London Wall. These piles had served as supports for dwellings. “The large quantities of loose nails indicated that the superimposed dwellings were of timber” (_Builder_, December 13, 1902). Timber piling has also been found at St. Martin’s le Grand and other sites. There was clearly much soft wet ground in the City. The better-class dwelling in Bucklersbury, to which belonged the fine mosaic floor now at the Guildhall, seems to have been largely of timber. In December last (1921) Mr. Lambert described at the Society of Antiquaries a remarkable piece of wharfing on the river bank at Miles Lane. This was a solid wall of squared balks of timber about 2 ft. square, laid one over the other and having ties into the ground behind. The construction showed an interesting set of tenons, halvings and housings. A bored wood pipe was also found. In Thames Street a house found in 1848 had a well-made drain made with 2 in. planks forming bottom and sides, which is said to have been covered in with tiles.