148 JOURNEY FROM may conclude that the Hght was admitted from above ; and it is by no means improbable that a space was left uncovered in the centre for that purpose, this mode of building being common in hot climates, and it would at all times have been easy to guard against the inconvenience of rain, as the surface exposed would have been inconsiderable.

No appearance of doors, or of apertures of any kind, is observable in the sides of these structures ; and they must either have been entered from the top, or by some subterranean communication.

There are instances still remaining, in the eastern parts of the Syrtis, of fortresses more difficult of access than these, where they who entered have evidently been drawn up with ropes by the persons already stationed above ; and we may conclude, as no traces of any subterranean entrance were discernible in the forts, which we have just described, that they were entered in a similar manner.

In the walled forts we found entrances to the outer works by means of gates, but could in no instance discover any door in the habitable part. We often wished for an opportunity of excavating some of these buildings, that we might be enabled to give their plans more correctly ; but, as it was important to secure the coast-line before the rainy season set in, we did not think ourselves justified in delaying the advance of the party any longer than was necessary for the attainment of that object.

As a general remark, we may here observe, that, in passing from west to east of the Greater Syrtis, the fortresses were found to be