adjoining to the Chequer-gate j they found Two or 
Three Stone Coffins, which had probably lain there 
ever flnce the Demolition of the antient Parifh- church 
of St, Mary Magdalen , to make way for the Founda- 
tion of the Cathedral, and its Appendages : But going 
lower, about io or 11 Feet deep, they found fome 
Building j and at 13 Feet, to their no little Surprize, 
they flruck into the Corner of a Vault. Mr. Symp- 
fon took it to be a Roman Hypocauftum : He had 
the Dimenfions of it taken, as in the Plan j fee Tab. 
VIII. Fig. 1. and the Profile, Fig. 2. 
A. The F r refurnium , [Stoking-place] Entrance or 
Place, where the Fornacator [the Stoker] flood to 
manage the Fire. It is 3 Feet 6 Inches fquare* its 
Height not certainly known, becaufe of the Rubbifli 
which lay at the Bottom. 
B. The Fornax , Furnace, or Fire-place, built ofBrick, 
and arched over with the fame. Its Length from E 
to G t $ Feet 6 Inches; its Height 3 Feet at E t but 4 
Feet at F f rifing gradually ; 3 Feet 6 Inches long from 
E to F, and 2 Feet wide between E and F ; 2 Feet 
long from F to G } and but 19 Inches wide between 
-Fand G. 
C, The Alveus [or Body of the Kiln], 21 Feet 4 
Inches long ; 8 Feet 4 Inches broad ; and 2 Feet 4 
Inches high. The Floor is made of a ftrong Cement 
compofed of Lime, Sand, Brick-duft, &c. which the 
Mafons of that Country call Terrace-mortar. Upon 
this Floor ftand Four Rows of low Pillars, made of 
Brick, 1 1 in a Row ; the outfide Rows round, the 
Two inner Rows fquare: The round ones are about 
1 1 Inches Diameter, the others 8 Inches fquare : Each 
Handing on a Brick 1 1 Inches fquare, as at Fig. 4. and 
