o flood the whole lake.
These lakes form part of the third line of defence or outer ward,
which includes also on the west the "horn-work" and on the east the
grand front. The horn-work is about three acres in extent, surrounded
by a wall 15 feet high, which is of the nature of an escarpment, the
ground rising above it. It is entirely surrounded by a moat, and
connected with the middle ward on one side and the mainland on the
other by drawbridges. It would probably be used for grazing purposes,
and thus would be of great value to the garrison; but so far as the
actual defences of the castle are concerned, a lake would have been
much more effective; the nature of the ground would however have
prevented this. The horn-work was intended to cover the only side upon
which the castle was open to an attack from level ground, and to
occupy what would otherwise have been a dangerous platform.

The eastern side of the outer ward--the grand front--is a most
imposing structure. It is a wall about 250 yards long, and in some
parts 60 feet high, furnished with buttresses and projecting towers
from which the intervening spaces are easily commanded, culminating
in the great gate-house near the centre, and terminating at both ends
in clusters of towers which protect the sally-ports. On the outside is
a moat spanned by a double drawbridge. The northern part of this
front, which was probably occupied by stables, would in dry weather be
the least defensible part of the castle; but it was cut off from the
rest by an embattled wall running from the gate-house to the inner
moat and pierced only by one small and portcullised gate. The southern
half was more important and stronger. It crossed the stream at the
dam, the walls being 15 feet thick where subjected to the pressure of
the water, and the strong group of towers at the end--on the other
side of the stream--guarded the dam on which the safety of the castle
largely depended; the wall and towers here form a semicircle, curving
back into the edge of the lake, so as to avoid the danger of being
outflanked.

On the inside of the grand front were various buildings, such as the
mill. This eastern line was divided from the middle ward by a moat 45
feet wide--a space which is too wide to be spanned by a single
drawbridge, and as there are no signs of the foundations of a central
pier, it seems probable that the bridge rested on a wooden support,
which could be removed when necessary, and the ass