_Tile Walling._—The brick commonly used in Rome was a crude or unbaked block; the burnt walling tile was, as said above, developed from pottery, and it always remained pottery-like in texture and thin in substance. As Mr. T. May has said of bricks: “They were made of heavy clay, well tempered and long exposed; the modern practice is to use the lightest possible clay right off without tempering.” Walling tiles were used in Londinium not only as bonding courses, but for the entire substance of walls. It is usual to write “Roman tiles or bricks” interchangeably, but in origin and character the thing was a tile, and, indeed, roofing tiles with flanged edges were used as a walling material occasionally. Tiles were of various sizes and shapes, but an oblong, 1½ ft. by 1 ft. and about 1½ in. thick, was most usual. In the Guildhall Museum are several triangular tiles which must, I think, have been used for facing walls with concrete cores. Solid tile walling was used in Londinium so extensively that it was evidently a common material for better buildings. The Lombard Street excavations of 1785 exposed “a wall which consisted of the smaller-sized Roman bricks, in which were two perpendicular flues, one semicircular and the other rectangular; the height of the wall was 10 ft. and the depth to the top from the surface was also 10 ft.” Here we have evidence of a brick wall rising the full height of one story at least (_Archæol._ viii.). Roach Smith noticed a wall in Scott’s Yard “8 ft. thick, entirely composed of oblong tiles in mortar.” Mr. Lambert has recently described some walls of brick 3¼ ft. thick found at Miles Lane. A building in Lower Thames Street had walls of _red_ and _yellow_ tiles in alternate layers. This fact I learn from a sketch by Fairholt at the Victoria and Albert Museum, and such use of bricks of two colours was a common practice. In Hodge’s sketches of the tile walls of a great building discovered at Leadenhall Market it is noted that some of the courses were red and buff. Price recorded of walls, 2½ ft. thick, found in the Bucklersbury excavations, that “the tiles were the usual kind of red and yellow brick.”