We may observe with regard to the structure of these forts, that
some of them have the habitable part of the building (which is
always of a quadrangular form, and placed in the centre) surrounded
by a double wall of very solid work; leaving a space between the
walls, of ten, twenty, and thirty feet, sometimes of more, in which
wells are occasionally found, and which may have served for the
accommodation of the horses, sheep, or cattle of the garrison.
Others have been built in one solid mass, with sloping sides, resembling
the base of a pyramid, having only a ’square space left in the
centre for the accommodation of the troops and the stowage of
stores and provision. On these there is always a platform, and
sometimes two, the sides of which form a glacis at a slope of from
thirty to forty-five degrees, some of them being steeper than others:
it seems probable that a parapet originally existed on the platforms
of some of the forts, behind which the troops might more securely
encounter their enemies; but on most of them there are now no
traces of any defence of this nature, and the platform is left exposed.
The lower platform is usually raised about ten and fifteen feet from
the ground, and the upper one about eight or twelve feet above that.
Trenches are rarely seen round the last mentioned buildings, but
those enclosed within walls usually possessed that additional defence.
Both are constructed with stone found in the neighbourhood, generally
without any cement, particularly the sloping ones, although a
very good cement may sometimes be observed in them: the most
considerable forts are built with large and regularly-shaped stones,
while the more unimportant are composed of stones of unequal forms
and sizes, care; being always taken, however, to leave a smooth surface
on the slope of the glacis, in order to make the ascent more
difficult. If we suppose that the greater number of these fortresses
were built as defences against the attacks of the predatory natives,
and not to resist the regular siege of a disciplined army, it may
certainly be allowed that they were well calculated to afford security
to their garrisons on such occasions; but their resources must soon
have been exhausted by a continued blockade, the space enclosed
being inadequate to contain many stores or much provision. As,
however, there could scarcely have been any accommodation for
horses of cattle in the pyramidal-shaped forts, which are by far the
most numerous, more provision might certainly have been stowed
in them than would at first sight be imagined. From the extreme
height of the habitable part of these buildings in proportion to its
breadth, we may conclude that it possessed an upper story, or, it
may be, two; for otherwise a great portion of space would be thrown
away: this fact, however, from their ruined state, could not be properly
ascertained.
The roofs were most probably arched, for no wood is to be found
in the Syrtis, and large blocks of stone could not always be procured,
and would at any rate have been less convenient to employ than
the small ones, which might be used in the arches*. From the circumstance
of finding no aperture in the sides of the buildings, we
* Arched roofs are also common in the forts of the Cyrenaica; b u t the sides both of
the upper and lower stories, which fronted the centre, were probably left open, after
the manner of ^galleries .