flows out of the
hot water cauldron may be replaced from that for tepid water, and in the
same way the cauldron for tepid water may be supplied from that for
cold. The arrangement must allow the semi-cylinders for the bath basins
to be heated from the same furnace.

2. The hanging floors of the hot bath rooms are to be constructed as
follows. First the surface of the ground should be laid with tiles a
foot and a half square, sloping towards the furnace in such a way that,
if a ball is thrown in, it cannot stop inside but must return of itself
to the furnace room; thus the heat of the fire will more readily spread
under the hanging flooring. Upon them, pillars made of eight-inch bricks
are built, and set at such a distance apart that two-foot tiles may be
used to cover them. These pillars should be two feet in height, laid
with clay mixed with hair, and covered on top with the two-foot tiles
which support the floor.

[Illustration: The Stabian Baths at Pompeii

S, S. Shops. B. Private Baths. A-T. Men's Bath. A'-T'. Women's Baths. E,
E'. Entrances. A, A'. Apodyteria. F. Frigidarium. T, T'. Tepidarium. C,
C. Caldarium. K, K, K. Kettles in furnace room. P. Piscina.]

3. The vaulted ceilings will be more serviceable if built of masonry;
but if they are of framework, they should have tile work on the under
side, to be constructed as follows. Let iron bars or arcs be made, and
hang them to the framework by means of iron hooks set as close together
as possible; and let these bars or arcs be placed at such distances
apart that each pair of them may support and carry an unflanged tile.
Thus the entire vaulting will be completely supported on iron. These
vaults should have the joints on their upper side daubed with clay mixed
with hair, and their under side, facing the floor, should first be
plastered with pounded tile mixed with lime, and then covered with
polished stucco in relief or smooth. Vaults in hot bath rooms will be
more serviceable if they are doubled; for then the moisture from the
heat will not be able to spoil the timber in the framework, but will
merely circulate between the two vaults.

4. The size of the baths must depend upon the number of the population.
The rooms should be thus proportioned: let their breadth be one third of
their length, excluding the niches for the washbowl and the bath basin.
The washbowl ought without fail to be placed under a window, so that the
shadows of those who stand round it may