The hot rooms, it should be remembered, are strictly bath rooms, and must be treated as such; that is to say, the whole of the floors, walls, ceilings, partitions, and fittings, must be capable of being frequently cleansed with water. The choice of materials to be employed for lining the walls, &c., is therefore limited. And in two ways. For not only must they be of this washable nature, but they must be of a character to resist the influence of the heat. Happily, this is an age of glazed-ware and vitrified goods of every description. Glazed and fire-burnt bricks and tiles, terracottas, faïence, and pottery generally, are now so extensively manufactured that there is little excuse for not constructing a bath throughout of materials at once washable and unaffected by high temperatures. Still, in baths where rigid economy must be studied, and lowness of cost is the great object, _plaster_ may be placed upon the walls of the hot rooms, and in its way will answer admirably, and be fairly washable. It has even one advantage--it does not become unbearably hot to the touch, should the bather lean against the walls, whereas, with a highly glazed surface the walls become burning hot, and need lining with a dado of felt or other non-conducting substance. And since this latter method overcomes the objection named, the best possible material for lining the walls is glazed brickwork. In cases where elaboration is desired, they may be lined with marbles and faïence. With a judicious selection of colours, however, a very pleasing appearance can be given by the employment of simple glazed brickwork, and at a very moderate cost. The flooring in cheap baths is admirably formed by simple unglazed tile pavement over concrete. A slight roughness is very agreeable to the feet. Glazed tiles are inadmissible, as they become too hot for the naked feet; and if the slightest moisture come upon them they are rendered dangerously slippery. In elaborate baths, marble, and marble mosaics may be used, but the surface must not be too smooth. In providing floorings, the greatest care should be taken to avoid anything liable to become slippery to the tread. Floors of ordinary-sized baths, where the soil is reliable, may be of 6 in. of concrete, with mosaics or tiles laid in cement. The benches for reclining and shampooing must be built up from this with half-brick risers and glazed fronts, having weathered marble slabs with rounded nosings, as illustrated at Fig. 3.