TRIPOLY TO BENGAZI. 147 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 disciphned 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 or 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 ; but the sides both of the upper and lower stories, which fronted the centre, were probably left open, after the manner of galleries.