I have still remaining, but not finished, the lower or subterraneous plan of the building, an entrance to which I forced open in my journey along the coast to Tripoli. This was made so as to be filled with water by means of a sluice and aqueduct, which are still entire. The water rose up in the arena, through a large square-hole faced with hewn-stone in the middle, when there was occasion for water-games or naumachia. Doctor Shaw[38] imagines this was intended to contain the pillar that supported the velum, which covered the spectators from the influence of the sun. It might have served for both purposes, but it seems to be too large for the latter, though I confess the more I have considered the size and construction of these amphitheatres, the less I have been able to form an idea concerning this velum, or the manner in which it served the people, how it was secured, and how it was removed. This was the last ancient building I visited in the kingdom of Tunis, and I believe I may confidently say, there is not, either in the territories of Algiers or Tunis, a fragment of good taste of which I have not brought a drawing to Britain. I continued along the coast to Susa, through a fine country planted with olive trees, and came again to Tunis, not only without disagreeable accident, but without any interruption from sickness or other cause. I then took leave of the Bey, and, with the acknowledgments usual on such occasions, again set out from Tunis, on a very serious journey indeed, over the desert to Tripoli, the first part of which to Gabs was the same road by which I had so lately returned. From Gabs I proceeded to the island of Gerba, the Meninx[39] Insula, or Island of the Lotophagi. Doctor Shaw says, the fruit he calls the Lotus is very frequent all over that coast. I wish he had said what was this Lotus. To say it is the fruit the most common on that coast is no description, for there is there no sort of fruit whatever; no bush, no tree, nor verdure of any kind, excepting the short grass that borders these countries before you enter the moving sands of the desert. Doctor Shaw never was at Gerba, and has taken this particular from some unfaithful story-teller. The Wargumma and Noile, two great tribes of Arabs, are masters of these deserts. Sidi Ismain, whose grandfather, the Bey of Tunis, had been dethroned and strangled by the Algerines, and who was himself then prisoner at Algiers, in great repute for valour, and in great intimacy with me, did often use to say, that he accounted his having passed that desert on horseback as the hardiest of all his undertakings.