[ 8o 3 ] 
in the long chapels; and twice their fum, 14 feet 
j-f inches, added to 1 58 feet inches, the infide 
diameter between the walls of thefe chapels, will 
give 172 feet 84 - inches for the diameter from out 
to out. This is equal to 1 83988,6 London parts; 
which anfwer to ipo Roman feet, of 8,4 fuch 
parts each. But this diameter being got by the ad- 
dition of many fmall parts, one of which is a fingle 
meafure, is of fmall authority. Though if the outer 
wall is 5 feet 47 inches thick in brick-work, and 
the backs of the niches in the long chapels- are in- 
crufted with marble (as I fuppofe they are), a proper 
allowance for the incrudation will make this diameter 
anfwer to a foot of ^70 London parts. 
The principal parts of the circular range within, 
are too unequal to anfwer to any regular divifion into 
compartments; and the two larged meafures in it 
fufficiently evince, how little ufe is to be made of the 
red; : for the width of the grand chapel oppodte the 
entrance, and the width of the entrance between the 
piladers in the range, will not anfwer to the fame 
meafure of the foot, by any probable divifors. 
But the inequality of the faces of the piladers, that 
terminate the folids in this range, affords the cleared; 
proof, that no certain meafure of the foot is to be ob- 
tained from the leffer parts of this building : for two 
of them, at the extremities of the fame folid, differ 
in breadth by a Paris inch and three quarters. One 
of the two on each fide the grand chapel exceeds the 
other in breadth, by a Paris inch and a quarter ; and 
it exceeds the lead in the circular range, by no lefs 
than 4i fuch inches, though the diameter of the co- 
lumn before it is lefs than that of fome in the range. 
Vol. LI. 5 L The 
