APPENDIX

SOME RECENTLY DETERMINED POSITIONS IN THE LIBYAN DESERT

In view of their possible utility in connection with future exploratory surveys, I give below a list of some of the more important of the positions which I have recently determined by astronomical observation in the southern part of the Libyan Desert, with brief descriptive notes on the places to which they refer. The observations were made whilst accompanying H.R.H. Prince Kemal el Din Hussein on his exploratory motor-car expeditions of 1923, 1924, and 1925. The longitudes of Qasr Farafra, Abu Mungar, Pottery Hill, and Regenfeld depend on the transport of a box-chronometer; the others on wireless time-signals from Europe. The positions of peaks were found by triangulation from the actual observation-spots. The altitudes of camps are from careful barometric determinations; those of the peaks depend on trigonometric levelling from the camps.

Place. Lat. N. Long. E. Altitude above sea. Metres.

° ′ ″ ° ′ ″

Merga, Camp 600 metres S.W. of west corner of salt lake. (Lake surface is 17 metres below level of camp.) 19 2 29 26 18 32 526

Bir Terfawi, Camp close to well and palms 22 55 12 28 52 51 244

Gebel Kissu, Summit 21 34 59 25 8 26 1726

Gebel Owenat, highest point 21 54 34 25 0 47 1907

„ „ remarkable triple peak 21 53 51 25 1 39 1718

„ „ S.W. peak 21 49 35 24 53 52 1450

Chunk Hill, Summit 21 52 46 25 13 56 985

Owenat, Camp 600 metres S.E. of western spring, on plain at foot of mountain 21 48 35 24 51 45 568

Owenat, Camp at mouth of gully, about 800 metres S.S.E. of eastern springs 21 53 8 25 7 58 626

Gebel Kamil, Summit (160 metres above plain) 22 16 31 26 38 11 800

Regenfeld, Rohlfs’ cairn of 1874, rediscovered 1924 25 10 49 27 24 22 470

Pottery Hill, Summit (39 metres above plain) 24 26 27 27 38 54 506

Sheb, Camp close to well, 240 metres N.N.E. of fort 22 19 48 29 45 46 228

Mut, Government Rest-house 25 28 37 28 58 24 119

Abu Mungar, Camp at small ruin, 400 metres E.S.E. of well 26 30 22 27 35 29 117

Qasr Farafra, Camp E. of village, 200 metres S.W. of Tomb of Sheikh Dakhil 27 3 26 27 57 52 90

Merga.—To geographers the most important of the new determinations will undoubtedly be that of the uninhabited oasis of Merga, which had not previously been visited by a European, and of which the situation could hitherto only be guessed at from Arab statements. Merga lies in a shallow depression about 50 metres deep, broken by sandstone hills and sand-dunes, and extending for some 20 kilometres north-east and south-west. The salt-lake, near the centre of the depression, measures about 300 metres by 150. It is surrounded by tall rushes and sandhills except at its south-western end. There are numerous date-palms, both near the lake and at considerable distances from it, as well as acacia trees and tamarisk bushes. The neighbourhood of the lake swarms with mosquitoes. Good and plentiful water was got by shallow digging about 1 kilometre south-south-east of the observation-spot, and could probably be obtained by digging almost anywhere in the depression. It is possible that the names Bidi and Tura el Bedai, shown with a question mark on some Sudan maps, may refer to different spots within the same depression. Owing to the plentifully scattered vegetation, the place cannot easily be missed, either by travellers passing within several miles of the lake, or by aircraft; but the landing of aeroplanes in the neighbourhood of the lake might be difficult owing to the extensive sand-drifts.

Bir Terfawi.—Scarcely less important than the accurate fixation of Merga is that of Bir Terfawi, the farthest south-west of all the Egyptian artesian water-sources hitherto known. It will be remarked that this latest determination places the well some 22′ south and 15′ east of the position which I had provisionally assigned to it from the rough data furnished by Lieut. Moore’s traverse of 1916.[60] A knowledge of the true position of Terfawi is specially desirable for a traveller who wishes to reach it, owing to the absence of any conspicuous landmark near it and to the sandy nature of the surrounding country, which causes tracks to be soon obliterated. There are numerous sandhills covered with tamarisk bushes around Terfawi, and a little grazing for camels. Besides the well at which observations were taken, water was found by digging in the sand at the foot of some tamarisk mounds about 13 kilometres farther west, and it is probable that good and plentiful supplies could be obtained at shallow depths near any of the other mounds. The palmtrees at Terfawi are few and small, and are less conspicuous than the tamarisk-bushes. These latter should enable the place to be easily found by aircraft; but landing would require some caution owing to the prevalence of drifted sand.

Gebels Kissu and Owenat.—The peaks of these mountains (especially that of Kissu, because of its isolated character and sharply marked summit) will form useful points for the connection of future surveys, being visible from very long distances.

Chunk Hill is a prominent isolated hill, nearly conical and of dark colour, which forms a good landmark in the broken country to the east of Gebel Owenat. It rises some 335 metres above the ground at its foot.

The Springs of Owenat.—Of the two water-sources of Owenat whose positions are given, the western one is the better, and is moreover very easy of access, being practically on the level of the plain which extends southwards from the mountain mass, and easily discoverable by the numerous animal-tracks converging to it; it is a pool among great boulders, obviously fed by percolation through cracks and fissures in the granite mountain which towers above it. The eastern water-source is less easy of access; it lies about 1 kilometre up a stony gully, and consists of a series of pools in the rocky floor of the gully, fed by trickling springs at the level where the granite is overlain by sandstone. The plain to the south of the western spring would form an excellent landing-ground for aircraft.

Whilst in the neighbourhood of Owenat, I had hoped to re-determine the longitude of Hassanein Bey’s camp of 1923 with the aid of wireless time-signals, or at least by triangulation-connection to one of my observation-points, because a really accurate fixation of the longitude of a point about midway along his route from Jarabub to Furawia would possibly furnish the means of slightly correcting the longitudes assigned to Hassanein’s camps at Kufra and Erdi. I was unfortunately prevented from carrying out the desired connection; but from a hurried car-traverse which I made, skirting the western side of the mountain mass, in the course of which I must have passed pretty close to the site of Hassanein’s Owenat camp, I think that camp really lies about in longitude 24° 49′, or some 5 miles to the west of where I had previously calculated it to be from Hassanein’s traverse data;[61] and that in consequence the longitudes assigned to Kufra and Erdi from the same data may be some 2 or 3 miles too great.

Gebel Kamil is a sharply pointed hill of dark sandstone, forming a useful landmark between Terfawi and Owenat. It was visible from the east for more than 40, or from the west for about 20, kilometres. The name was given to it by Prince Kemal el Din in honour of his father, Hussein Kamil, the late Sultan of Egypt.

Regenfeld, it will be remarked, was found to be very nearly in the position assigned to it by Jordan in 1876,[62] and my estimation of the level of the place is only 20 metres higher than Jordan’s. The neighbouring dune I found to be 30 metres high, agreeing exactly with Jordan’s measurement of fifty years previously; and as far as I could judge, the situation of the dune relative to the cairn seems to have remained unchanged through this long interval, showing that there has been at any rate no great lateral displacement of the dunes. The iron tanks left by Rohlfs were quite intact, in spite of their half-century of exposure; they had become covered with a hard dark brown film, apparently of magnetic oxide of iron, not rusted in the ordinary way, a fact which speaks strongly for the dryness of the region. Empty wine-bottles left by the Rohlfs expedition were frosted by the sand-blast wherever they were exposed; but surprisingly little of the glass had been removed in this way.

Pottery Hill is the northern one of a pair of nearly conical dark sandstone hills about 40 metres high, which are conspicuous from some distance owing to their situation on a nearly level sand-plain. I gave it its name from the numerous jars which I discovered at its foot in 1917.

Sheb Well is a pool of fairly good water in a shallow excavation at the foot of a clump of dom palms, half surrounded by sand-dunes and tamarisk mounds, 240 metres north-north-west of a fort; the latter occupies a fairly conspicuous position on a sandstone hill about 25 metres high. Another well, situated at the foot of a clump of dom palms about 11 kilometres farther north, is called Bir Terfau; this should not, of course, be confused with the Bir Terfawi already mentioned.

To the north of Sheb, on the Arbain road, are three other water-sources which I visited in 1925 and of which I determined the approximate positions by a carefully controlled car-traverse: Bir Kassaba, in lat. 22° 41′, long. 29° 55′; Bir Abu Hussein, in lat. 22° 53′, long. 29° 55′; and Bir Murr, in lat. 23° 22′, long. 30° 5′. Bir Kassaba is a pool of good water at the foot of a clump of palms; Bir Abu Hussein, which likewise yields good water, is a small excavation in sand near a hill of pink coarse-grained granite, and usually requires to be dug out afresh by each traveller; Bir Murr, on a little plain surrounded by hills, consists of several holes, with fairly good water, excavated in the sand at the south side of the outcrop of a steeply inclined bed of speckled calcareous sandstone.

I have not myself traversed the desert to the east of Sheb, but according to an intelligent Arab who has recently made the journey from Sheb to Dungul, there are only two spots between these places at which water is obtainable; they are Bir Abu Seifa, a small well of good water about 50 kilometres from Sheb, and Bir Haleifa, about 15 kilometres farther on, where there is a fort and numerous wells. This latter place must, I think, be the same as the Bir Nakhlai, of which the position found astronomically by Colonel Talbot in 1893 was lat. 22° 29′ 1″, long. 30° 19′ 36″.

The Rest-house at Mut, in Dakhla Oasis, is a low whitewashed building of three rooms, situated on open ground a little to the south of the village. It is conspicuous by reason of its isolation from other buildings, and forms a convenient starting-point for car journeys to the south-west of Dakhla, as well as for journeys to Kharga by the southern track which was mostly followed by cars during the war.

Abu Mungar proved to be very close to the position given by Mr. Harding King’s observations of 1912.[63] To the south-east of Abu Mungar, about halfway to Dakhla, are two remarkable hills forming outliers of the plateau. These hills, which are good landmarks, were first discovered by Mr. Harding King, and as they appear to possess no native name, I have called them “King’s Hills” on the map. The farther one of the two from the plateau lies in lat. 25° 58′, long. 28° 11′, from compass-bearings which I took to it on a careful car-traverse in 1924. The other is about 2 kilometres farther north.

Qasr Farafra.—The position of the village of Qasr Farafra which I gave in my paper of 1919[64] is proved to be very nearly correct by the latest observations. The main advantage of the new determination is that it is referred to an easily identifiable landmark, the tomb of Sheikh Dakhil, instead of to the ill-defined centre of the village.

Levels in or near Baharia Oasis.—I think it may be well to record here that owing to an unfortunate mistake about the datum to which the level of the old military railway-terminus at B6 was referred, all the altitudes given on pp. 10 and 11 of my above-mentioned Survey Department Paper of 1919 require a correction of 19 metres to be added. At the time when I triangulated Baharia in 1917, I was informed that the level found by the military authorities for the terminus was measured from the sea-level datum, and I employed the value given for it as my fundamental level. But I have since ascertained that an arbitrary datum was employed by the military engineers; and trigonometric levelling from the Nile Valley has shown that this arbitrary datum was about 19 metres above sea-level.