The Tagedufat valley bottom, unlike the Milen and Taberghit valleys, is marked by a more continuous stream bed along which water flows every year for a short time during the rains. The most remarkable feature of the valley is a series of flat bare patches formed by the pools of rain-water; they are of no great size, but the surface is stained bluish-white by chemical incrustation. The Milen and Taberghit valleys, while possessing a few similar rain-pools, none of which survives for more than the briefest period, do not exhibit this complexion. The point is of particular interest in connection with a report given to me by my guide, Sidi, who was with me on the way south. He is a widely travelled and knowledgable man. He stated that the Tagedufat depression extended eastwards across the desert all the way to Fashi, and was marked along the whole of its course by such patches of chemical incrustation. My travelling companion, Buchanan, observed that the ground shortly before reaching Fashi was stained in the manner described. In the open desert, where in the immensity of space it is difficult to determine the direction of a very slightly accentuated valley, such noticeable features are valuable evidence.
Considering the size of the Tagedufat basin south of Milen, the valley shown as extending towards Termit on the French 1/2,000,000 map and called Tegemi (Téguémi), is perhaps a confluent, or even an inaccurate representation, of the main valley itself. A recent Camel Corps[65] reconnaissance from Talras to Eghalgawen possibly followed up one such affluent in the east bank of the main channel of Tagedufat. The importance of the Tagedufat valley from the hydrographic point of view cannot be over-stated.
Directly the Tagedufat valley is crossed the rock outcrop on the north bank becomes a striking feature. Increasing in size towards the west, it falls away below the surface to the east. Crescentic dunes reappear between the outcrops and continue almost all the way to Milen. On the north side of Tagedufat, near the track, for which it serves as a landmark, is a prominent mass of black rock called the Kashwar (Stone) n’Tawa or Tawar. Far away to the N.N.E. the relief becomes bolder, rising to a group of small summits clothed with loose sand, called the Rocks of Oghum. The remains of some stone houses, at one time the southernmost permanent settlement of Air, appear in the loose sand near the hills. North of Oghum in a little depression filled with acacias is Gharus n’Zurru.[66] After a further stretch of dunes a small valley running northwards diversifies the general lie of the ground. It is called Maisumo, and contains another deep well which is still in use. This valley after a short distance runs into the Milen depression, with the conical hill of Tergulawen visible to the east and the little massif of Teskokrit to the west. The northern part of the latter group extends eastwards from the main summits as a steep ridge forming the northern bank of the Milen valley itself.
East of Tergulawen again is a small and almost unknown group of hills called Masalet, where in recent years Kaossen, afterwards leader of the Air revolt in 1917, dug a well. It only yielded brackish water, which, though good enough for camels, proved too medicinal for the Tuareg, who filled it in again. It had been dug for political purposes largely in order to facilitate parties from and for the Southland participating in the yearly caravans which fetch salt from Bilma. Masalet was designed to obviate these parties making a detour along the River of Agades or via Eghalgawen: it provided an easterly watering-point in Azawagh corresponding with Tazizilet further north in Air itself. The unsatisfactory nature of the supply, especially for caravans engaged in crossing the eastern desert, did not, however, justify the risk of leaving so remote a watering-point available for Tebu raiding parties. The fact that Masalet was constructed in recent years is interesting, as showing that the Tuareg have not lost the art of locating deep water.
The western road from Tanut to Agades via Aderbissinat and Abellama runs over much the same sort of country as that which I have just described between Farak and Milen. Aderbissinat well, seventy-five miles from Tanut and ninety-three miles from Agades, is a point of such strategic importance that the French from Zinder built a fort there during the war in order to secure their communications with Air. It has not been garrisoned of late, but proved of paramount importance during the operations of the column which marched from the south to relieve Agades during the rebellion of 1917. With the exception of the deep but copious well of Abellama, there is no useful permanent watering-place between western Damergu and Agades, as the spring of Ihrayen in the Tiggedi cliffs has too small an output to provide for many animals. Nineteen miles north of Aderbissinat the bush ceases. As at Taberghit further east, the country rises some 200 feet to an average level of 1700-1800 feet above the sea. Beyond Timbulaga sand dunes appear on the level buff-coloured steppe, which is covered with the usual scanty vegetation of desert grass in tussocks.[67] The ground then slopes gradually down to the deep well of Abellama in Lat. 16° 16′ 30″ N. and Long. 7° 47′ 20″ E. G. Abellama as a stage corresponds with Milen on the other road.
On the easternmost or Tergulawen road Barth[68] shows that the country is again substantially the same. South of the “spacious” well, which is in a depression “ranging east and west,” with sand-hills on the south side bearing a sprinkling of desert herbage, the country is covered with small dunes on a “flat expanse of sand, mostly bare and clothed with trees only in favoured spots.” To the north is a great sandy plain running as far as the Ridge of Abadarjan, where the level descends to the upper basin of the River of Agades. The area is covered with “hád,” the most nutritious of desert plants and the most characteristic of the desert steppe of Africa. In all parts of the Sahara the distribution of the plant marks the division between the Desert and the Sown. This “hád” of the border line advances or recedes, sometimes from year to year, according to the rainfall. It is the tidal mark of the desert.
The northern part of Azawagh is geographically important, as it contains the transverse valleys which collect the southern rainfall of Air and carry it westwards into the Niger basin. The course of the Beughqot (Beurkot) and Azelik[69] valleys is wrongly shown on the French maps. They do not unite until they have reached a far more southerly point than where they are shown to do so on the Cortier map. Furthermore, when they have joined, they turn S.W. and not S.E. A recent reconnaissance as far as Masalet proved that after these two valleys meet they turn west into a large depression which is probably the same one as that in which the well of Milen is situated, though it might, on the other hand, be the Tagedufat basin; this is a point which must for the moment remain undecided. On a solution of this problem depends the answer to the question as to whether Milen or Tagedufat is the principal basin into which the Air valleys east of Beughqot as far as Tazizilet drain. All that is clear is that they turn southwards and then westwards to join one of the two systems in question, and do not peter out in the desert as Cortier’s map suggests.
West of Milen well the valley in which it is situated eventually joins the lower Tagedufat, which runs on S.W. or W. towards the Gulbi n’Kaba or the Tafassasset-T’immersoi basin. That the Tagedufat system does not enter the River of Agades over the Tiggedi cliff at some point near Ihrayen is probable owing to the fact that all this country has been subjected to a slight southerly tilt. The Tiggedi cliff, the Eghalgawen-T’in Wana massif, the cliff east of Akaraq and its continuation along the great valley, finally represented by the ridge of Abadarjan, as Barth rightly judged, are the northern boundary of this area, which slopes gently from north to south. The River of Agades receives hardly any left-bank tributaries.
Milen well could never be found without a guide. The wide valley, with sand dunes on the south side and a steep north bank where the now omnipresent rock of Air appears, is bare, dry and stony. It shimmers in the heat. Teskokrit appears as a black mass in the west on a bank of milk-white mirage set round a group of trees. The bottom of the valley is a gravel plain with a small patch of bare rock in it which an unwitting traveller would most probably pass unheeding. In this patch of rock is a small hole with a large circular stone near by. The hole, barely three feet across, is the mouth of a well driven through hard sandstone all the way down to the water-bearing stratum, seventy feet below the ground. The mouth can scarcely be seen fifty yards away. The rounded stone is several inches thick and was said to have been used to cover up the mouth of the well to prevent its becoming silted up with driving sand.
I came there in June, after more than forty hours’ march from Hannekar with four tired camels and two men, an Ifadeyen guide and an Arab of Ghat in the Fezzan. We had very little water left, so little, in fact, that it was all used in one pot to cook some rice for us three. The place was deserted and very lonely. The wind was driving the sand so hard that it stung the naked calves of my legs as I stood at the well with Ishnegga the guide, drawing water for the thirsty camels. Camels in hot weather drink a great deal, and hauling water in a two-gallon leather bucket from a seventy-foot well is hard work in a temperature of over 150° F. in the sun. The camels drank interminably. The last and best camel was still thirsty and remained to be watered. The beast was rather weak. It had a bad saddle sore, a hole about the size of a large man’s hand, in its back, and it was festering and full of maggots. We had all just done a journey of over 500 miles from Tanut to Termit and back, in thirty-five days, including nine days of halts, averaging, in other words, nearly twenty miles per marching day for twenty-six days. The camel had begun to drink. Then as we were drawing a full bucket the well rope broke six feet from my hand and fell to the bottom of the well with a splash. A vain hour was spent, while the rice cooked and got more and more full of sand, trying to fish up the rope and bucket with an iron hook made of the nose-piece of a camel bridle fastened to a knotted baggage rope. This too was lost after hooking the tangle, which it joined at the bottom of the well. Prospects looked gloomy as our thirst increased. I have distinct recollections of the sky and valley getting whiter and more metallic and the heat more intolerable. Finally, just enough rope was found by untying all the baggage to ladle up water a half-gallon at a time in a small canvas bucket. But the poor camel had to wait a long time to finish its drink, for the first of the supply to reach the top was used to refill the tanks.