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the pavement. The ceilings, if of masonry, will be pre¬
ferable ; if, however, they are of timber, they should be
plastered on the under side, which must be done as fol¬
lows. Tron rods, or arcs, are prepared and suspended by
iron hooks to the floor as close as possible. These rods
or arcs are at such distances from each other, that tiles,
without knees, may rest on and be borne by every two
ranges, and thus the whole vaulting depending on the
iron may be perfected. The upper parts of the joints
are stopped with clay and hair. The under side towards
the pavement is first plastered with pounded tiles and
lime, and then finished with stucco or fine plastering. If
the vaulting of hot baths is made double it will be better,
because the moisture of the steam cannot then affect the
timber, but will be condensed between the two arches.
The size of baths must depend on the number of persons
who frequent them. Their proportions are as follow: their
width is to be two thirds of their length, exclusive of the
space round the bathing vessel (schola labri) and the
gutter round it (alveus). The bathing vessel (labrum)
should be lighted from above, so that the bye standers
may not cast any shadow thereon, and thereby obstruct
the light. The schola labri ought to be spacious, so that
those who are waiting for their turn may be properly ac-
commodated. The width of the alveus between the wall
of the labrum and the parapet must not be less than six
feet, so that it may be commodious after the reduction of
two feet, which are allotted to the lower step and the
cushion. The laconicum and sudatories are to adjoin
the tepid apartment, and their height to the spring¬
ing of the curve of the hemisphere is to be equal to
their width. An opening is left in the middle of the