_impluvium_ in the centre. A _crypto porticus_ would thus be formed
on the two longer sides of the bath, but the _schola_ on the east
and west ends was open to the sky. Practical experience, either on
the completion of this plan, or previously to its entire execution,
led to its abandonment. At any rate a roof over the whole was found
essential to the comforts of the bathers. The piers were accordingly
strengthened. Pilasters were erected, projecting 2ft. 9m. into the
bath, with smaller pilasters on the other side projecting on the
_schola_, 1ft. 4in. by 1ft. 11in. wide; and _vis-a-vis_ to these
pilasters corresponding ones were affixed to the side walls.
Unfortunately this brought into prominence the irregularity of the
size and position of the _exedrae_, and the pilasters were affixed
correctly with reference to the arcade, as was absolutely necessary,
but more or less trespassing on the width of the opening of these
recesses, and notched into the original pilasters.

None of the piers, or pilasters, at present exist to a height
exceeding 6ft. to 7ft. The base is a rude form of the Attic base;
and we have found several fragments of the capital, or impost, of the
smaller pilasters, from, which the arches sprang, but I have not been
so fortunate as to recognise any of the larger capitals, and but few
fragments of the cornices, and but one piece that I can identify as
the frieze 1ft. 6in. deep by 2ft. 4in. long, on which are 5 incised
letters 6¼in. long S SIL. The _schola_ was then arched in north and
south, and the bath spanned by an arch. The vaulting that spanned the
side arcades, and the centre (where the abutment was not sufficient
for arches formed in the ordinary way of tiles or stone), were built
of brick boxes, open at the sides, and wedge-shaped, 1ft. long, 4¾in.
thick, and 7¾in. wide at the wider end, set in the usual mortar, a
greater or less number of rings of these boxes being used according to