I will endeavour to describe the bath as originally designed.  Along the margin of the bath, north and south, stood six piers, equally divided (about 14ft. apart), as far as the length of the bath, but allowing a lesser distance from the attached pilaster at either end.  These piers are cut out of a block (in plan, 2ft. 101/2in. from east to west by 2ft. 8in. from north to south), so as to form a pilaster of three inches projection on either face.  As the original pilasters on the north and south walls do not correspond with these piers, I am led to conclude that the schola and exedrae, north and south, were not vaulted at first, and were the only portion of the hall that was roofed, and that the roof was only of timber, supported by an arcade, the arches not exceeding 17ft. in height, and that the eaves of the roof of about 22ft. in height dipped towards the bath.  This was a very usual arrangement in the Atrium of a Roman house with the 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 61/4in. 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, 43/4in. thick, and 73/4in. wide at the wider end, set in the usual mortar, a greater or less number of rings of these boxes being used according to the span.  These arches were made out by an extra quantity of concrete