Russegger informs us,[57] that he believes he was the first traveller who had succeeded in making a series of barometrical measurements along the Nile Valley, from the Mediterranean to Sennaar and Kordofan, and thence to the 10th degree of north latitude. He gives the following altitudes, above the sea:-- Paris Feet. English Feet. The upper part of the Cataract of Assuan, 342 = 364·37 Korusko, on the right bank of the Nile, in Nubia, 450 = 479·43 Wadi-Halfa, 490 = 522·00 New Dongola, 757 = 806·52 Abu Hammed, 963 = 1026·00 Footnote 57: Reisen, Bd. ii., 545. I shall now give the length of the Nile along its course from Abu Hammed to the island of Philæ, at the head of the cataract of Assuan. I employ for this purpose the map in the atlas which accompanies the work of Russegger, which bears the date of 1846, and which, doubtless, was constructed on the best authorities. He mentions a map of General von Prokesch with great praise.[58] It flows:-- German M. English M. From NE. to SW., from Abu Hammed to Meroë, about 31 = 150 It makes a curve between Meroë and Old Dongola, of about 16 = 77 It flows between Old and New Dongola, from SE. to NW., about 16 = 77 Then, with some short windings, nearly due north to the island of Sais, for about 30 = 145 And from Sais to the island of Philæ, from SW. to NE., about 68 = 327 ---- ---- Making the whole length of the course, from Abu Hammed to Philæ, about 161 = 776 Footnote 58: "Über den Stromlauf und das zunächst liegende Uferland des Nils, von der zweiten Katarakte bis Assuan, besitzen wir eine vortreffliche Karte namlich:" "Land zwischen der kleinen und grossen Katarakten des Nil. Astronomisch bestimmt und aufgenommen in J. 1827, durch v. Prokesch. Nil Grundrisse der Monumente. Wien, 1831."--Reisen Bd. ii., Thl. iii. 86. Ascending the river, we have, between Philæ and Korusko, a distance of 24 German, or 115½ English miles, and without any rapid, except one near Kalabsche. Korusko being 115 feet above the head of the cataract of Assuan, at Philæ, we have an average fall of the river between these two places of a foot in a mile. Between Korusko and Wadi-Halfa there is no rapid. The distance being 20 German, or 96 English miles, and the difference of altitude being 42½ feet, we have an average fall throughout that part of the river's course of not more than 5·3 inches in a mile.