The walls of the houses are remarkable for their thickness, namely, three feet; while that of the wall of the town is four feet. They are constructed upon a plan commonly adopted by the Romans--namely, a facing of stone on each side, and the space between filled in with rubble and that remarkable stone-like enduring mortar which has suggested the name of a better kind of cement of the present time, known as "Roman cement." The height of the houses was thirty feet; but they had no upper storey, and there is no trace of staircase. Of the mode of warming the houses and, _par excellence_, the baths, the Rev. Thomas Wright[9] observes:--"The Romans did not warm their apartments by fires lighted in them.... The floor of the house, formed of a considerable thickness of cement, was laid upon a number of short pillars formed usually of square Roman tiles placed one upon another, and from two to three feet high. Those of the largest hypocausts yet found at Wroxeter were rather more than three feet high. Sometimes these supports were of stone, and in one or two cases in discoveries made in this country they were round. They were placed near to each other and in rows, and upon them were laid, first, larger tiles, and over these a thick mass of cement, which formed the floor, and upon which the tesselated pavements were set. Sometimes small parallel walls forming flues instead of rows of columns supported the floor.... Flue tiles--that is, square tubes made of baked clay with a hole on one side or sometimes on two sides--were placed against the walls endways one upon another so as to run up the walls." [9] "Guide to the Ruins of the Roman City of Uriconium at Wroxeter, near Shrewsbury." 1859. My friend Mr. George Witt, having recently visited the ruins of the ancient Roman bath still existing at No. 117, Bridge-street, Chester, describes it as follows:-- "The most interesting of all the Roman antiquities of this ancient city are the remains of a private Roman bath, showing the _Hypocaustum_, or heating place beneath, in a state of great preservation. The hypocaust is 18 feet long by 8 feet wide, and 3 feet high. The roof was supported on thirty-two stone pillars (of a single block), broader at the base and the top, and narrower in the middle; of these twenty-eight still remain. On the top of the columns are placed, by way of capitals, strong tiles from 17 to 23 inches square, and 3 inches thick, reaching from pillar to pillar, thus forming, at the same time, the roof of the hypocaust and the floor of the room above. Over all these is a bed of hard concrete, 9 or 10 inches thick, the whole suited to bear any amount of heat. The pillars are made of the red sandstone of the district, and are so far worthy of note, that they differ from the tile-columns of most of the Roman hypocausts found in other parts of England, which are chiefly formed of piles of 8-inch tiles, 2 inches thick.