88 A TROPICAL DEPENDENCY quarters, with the exception of the Wadi Dra, at five days' distance from Sidjilmessa, which was the meetingpoint of the Masmouda Berbers, a fraction of the Senajah tribe. For the accurate geography of this road the reader who is interested should refer to Cooley's ''Negroland of the Arabs," in which he will find a learned and most careful examination of the ancient geography of the country. From the conclusions drawn by Cooley it would seem quite clear that the road described by El Bekri coincides almost exactly with that shown in modern maps as connecting El Harib on the south-western frontier of Morocco with Timbuctoo, via Mabruk, which encampment Cooley identifies with the Audoghast of the Arabs. The only difference would appear to have been that the meetingpoint of Tamedelt mentioned by El Bekri as being eleven days west of Sidjilmessa, was slightly to the west of El Harib. Cooley fixes it at lat. 28° 45' N., long. 7° 10' W. Dr. Barth disagrees with Cooley, and would place Audoghast somewhat to the west of Mabruk. To reach Negroland by the western route there were, however, two possible variants of the road, both of which have been so accurately described by El Bekri, and after him by Ibn Batuta and other travellers, as to leave little room for doubt as to their direction ; one led via Audoghast, the other, as pursued by Ibn Batuta at a later date, ran more directly south via Tegazza to Aiwalatin or Walata. Both would appear to have been equally well known and equally used from the earliest times. Both required a journey of about two months from Sidjilmessa ; but the one skirted the western and the other the eastern border of the desert of Tizer or Ayawad. Both traversed the desert, using as guides the nomad Berbers of the locality. Ibn Batuta describes the portion of it just north of Aiwalatin as ''a vast plain, beautiful and bright, of which the air is so invigorating that the spirits rise and the lungs dilate." It is, however, quite waterless for many days, and in order to reach Aiwalatin the custom was to send a practised guide seven days ahead to give