THe INTERIOR BUILDINGS. 167 
itself is 3 feet 6 inches high and 16 inches wide, and the sides are 
built of rubble without mortar. The course of a drain between 
the east rampart and the adjoinmg buildings, numbered I., II., IIL, 
and IV., is indicated on the plan, and in connection with it there 
remains 7n sitw a curious inlet, consisting of a piece of open channel- 
ing similar to that found at the sides of the streets, but of greater 
breadth, and a built hopper with sloping flag bottom and flag cover 
(see drawing, plate IIIA.). It is opposite the eavesdrop between 
Nos. II. and III., and doubtless the channelling would extend the 
whole length of the eavesdrop, for the purpose of carrying off the 
water falling from the roofs of the buildings. 
A. characteristic method of preparing the foundations for the 
reception of the walls, to which reference has already been made, 
prevails. A trench is cut in the ground 9 inches deep or more, and 
of a width a little greater than the thickness of the intended wall, 
which is filled with well-tempered clay. The surface of the clay 
is paved with whinstone cobbles, accurately marking out the situa- 
tion of the walls, even to the width and projection of the buttresses, 
and the pavement is beat into the clay, the substance being there- 
by consolidated and rendered suitable for the support of the 
superincumbent masonry. It is an excellent foundation ; and its 
use, on account of its permanence, proved of much service in trac- 
ing out the plan. 
The footings usually project, forming scarcements on each side 
of the wall, but not always; and for the lowest course of stones, 
and mostly the second also, or what of the wall would be lower 
than the surface of the ground, instead of lime mortar, clay is used 
for bedding and jointmg. The work is exceedingly good, every 
erevice closed, and the whole a solid mass. Whether this method 
was followed with the view of protecting the walls from rising 
damp, or because it was thought better adapted to the circum- 
stances, the work being in contact with the earth, than lime mortar 
would be, the result is that now, after the lapse of so many ages, 
these footings, so built, where undisturbed by force, are yet in 
perfect order, whereas the lime mortar used in the overwalling has 
been wholly absorbed by the accumulated soil. 
These methods of constructing the foundations and footings 
are peculiar to the primary walls. 
The walling discriminated as secondary is characterised by 
inferior workmanship; and the primary parts vary in quality par- 
