Part of my work comprised the precise fixation of the points specified in the Arrêté, with a view to laying down the boundary accurately on a map. As was natural in the case of a boundary settled without careful reference to the ground, certain difficulties arose in the location. In the first place, there are two distinct Gebels Niqrub, and two distinct Gebels Um el Tiur. I assumed the higher mountain of each pair to be the one indicated. Secondly, the precise point of the mountain was unspecified; I assumed the highest peak to be the point referred to. Thirdly, the text of the Arrêté disagrees with the map accompanying it, in that the map shows the line curved to pass close to Gebel Mishbih, which is not mentioned in the Arrêté. I assumed the text of the order to be determinative, and that between the points specified the limit followed great circles on the globe, _i.e._, practically straight lines on the map. The locality called Deiga was not visited, and can only be approximately fixed; it is said by guides to be a narrow road near Gebel Muqsim, of which mountain several peaks were fixed by triangulation. The following table gives the positions found for the various points along the boundary from the sea to the meridian of 34° (1) from my survey operations, and (2) as scaled from the map accompanying the Ministerial Arrêté. A comparison of the two sets of positions will show how much the survey has added to our knowledge of the geography of this part of the desert. -------------------+-----------------------+------------------------ | Latitude N. | Longitude E. Point. +-----------------------+------------------------ | From my | From | From my | From | Survey. |Arrêté Map.| Survey. |Arrêté Map. -------------------+-----------+-----------+-----------+------------ Bir Shalatein |23° 8′ 5″|22° 39′ 0″|35° 36′ 28″|36° 2′ 30″ | | | | Bir Meneiga |22° 47′ 8″|22° 41′ 30″|35° 12′ 20″|35° 2′ 30″ | | | | Gebel Niqrub (El |22° 51′ 29″|22° 48′ 0″|34° 56′ 48″|34° 51′ 0″ Foqani) | | | | | | | | Gebel Um el Tiur |22° 17′ 54″|22° 18′ 30″|34° 41′ 1″|34° 32′ 0″ (El Foqani) | | | | | | | | Deiga (approx.) |22° 10′ 0″|22° 9′ 0″|34° 1′ 0″|34° 3′ 0″ -------------------+-----------+-----------+-----------+------------ =Variation of the Compass.=