From Ouenat to Erdi “Well” is a journey of 439 km. in a south-southwesterly direction, the first 284 km. being in the Anglo-Egyptian Sudan, the remaining 146 in French Equatorial Africa. There is no water in all this stretch, but patches of dried grass were met with at intervals in the latter half of the journey, and some 25 km. before reaching Erdi the valleys were full of green grass. Thus the northern limit of the equatorial rain-belt hereabouts is approximately in Lat. 18° 50′.
Erdi.—Erdi appears to be the name given to an extensive tract of country stretching between the twenty-first and twenty-fourth meridians of east longitude, rising gradually southward and ending in a broken east and west escarpment in about Lat. 18° 30′. The water-source visited by Hassanein Bey, called by the guide “Erdi Well,” is in Lat. 18° 31′, Long. 23° 10′, and is 958 meters above sea-level. It is not really a well, but a rock-pool, similar to those of Arkenu and Ouenat; the water is good.
Hassanein Bey’s “Erdi Well” is close to the locality marked “Erdi-ma” on Lieutenant-Colonel Tilho’s map of 1920, but it appears not to be the same water-source as the one visited by that traveler. Erdi Well is at the head of a small valley draining northward, and one has to ascend the hills to a height of 1020 meters above sea and cross a stretch of broken plateau before reaching the southward drainages which cut back into the scarp. Over this broken plateau Hassanein Bey proceeded in a southeasterly direction, descending the scarp in Lat. 18° 25′, Long. 23° 20′. The level at the foot of the scarp was 790 meters, so that the scarp hereabouts is some 230 meters in height.
After descending the Erdi scarp, Hassanein Bey’s track southward across the great sandy depression which separates the Erdi plateau from that of Ennedi, to Agah (88 km. from his camp north of Erdi Well), appears to have been almost parallel to, and some 20 km. east of, that followed by Lieutenant-Colonel Tilho in 1914.
Agah.—The water-source of Agah is a rock-pool similar to that at Erdi; but the water is bad, owing to fouling by animals. The pool is some 6 km. up a valley cutting back northward into the scarp which faces that of Erdi. The position found for the pool at Agah lies some 24 km. from the “Aga Spring” shown on Lieutenant-Colonel Tilho’s map. There are possibly several springs and pools among the hills in this neighborhood, all bearing the same name, which would explain the apparent discrepancy.
From Agah the track to Enebah (65 km.) runs in a rather zigzag course with a general southward trend. For the first 10 km. beyond the pool, the track ascends the valley; then, mounting rapidly, it soon reaches altitudes of over a thousand meters on the plateau.
Enebah.—Here is a small settlement of Badawi and a well of good water about 28 km. east of the wells of Keita shown on Lieutenant-Colonel Tilho’s map, on the same high plateau.
From Enebah to Bao is 120 km., by a rather zigzag track in a general south-southwesterly direction over an undulating and hilly plateau. The greatest altitude recorded by Hassanein Bey during his entire journey, 1184 meters above sea, was reached at a point on the road about 18 km. from Enebah. This altitude (3884 feet) is slightly higher than that (3600 feet) which Lieutenant-Colonel Tilho records as his maximum on the same (Erdebe) plateau at a point further west; so that the plateau probably increases in height to the eastward. The Kaptarko valley was crossed about 47 km. further on, and it is interesting to note that Hassanein Bey’s data give a position for this which is very close to the “Kapterko” of Lieutenant-Colonel Tilho’s map.
Bao.—Hassanein Bey’s Bao is not the “Bo” visited by Lieutenant-Colonel Tilho, which lies over 100 km. further north, but the place called “Orobo” on Tilho’s map and “Bao” on the map of Wadai and Darfur which was attached to the convention between the British and French Governments at Paris in 1919; this is evident from the following comparison of Hassanein Bey’s position with those scaled for the above-mentioned places from the maps referred to:
| Lat. N. | Long. E. | |||||
|---|---|---|---|---|---|---|
| ° | ′ | ″ | ° | ′ | ″ | |
| Bao (Hassanein Bey) | 16 | 28 | 24 | 23 | 1 | 47 |
| Orobo (Tilho) | 16 | 30 | 0 | 22 | 59 | 0 |
| Bao (convention map) | 16 | 28 | 0 | 23 | 4 | 0 |