Papyrus, 31, 32, 42 Payen, Champion and Gastinel, 63 Peake, Major, R. A., 41 Peat, 21 Percolation, see Infiltration. Perennial irrigation, 59, 68, 69, 88, 93 Phosphates, 22, 115 Pibor river, 37 Pics converted to metres, 98, 209, 210 Plates, List of, 9 Pliocene, 113 Porphyry, 114 Projects, 44, 58, 73, 84 ---- Raising Assuân dam, 75 ---- Wady Rayan Reservoir, 76 ---- Lake Albert Reservoir and river training, 81 ---- Flood protection for Egypt, 85 ---- Complete for the Nile, 87 ---- Sir William Garstin’s projects, 89 ---- Conversion of basin to perennial irrigation, 93 ---- Development of the Sudan, 100 Prompt, M., 74 R Rahad river, 17, 21, 44, 101 Rainfall, 17-21, 27, 30, 41, 43, 45, 56, 59, 103, 213 ---- tables, 214-220 Rameses, 48, 86 Red water, 61, 75 Reservoirs, 30, 73, 75, 76, 77 Ripon Falls, 12, 27, 28, 127, 139-141, 143, 166 Roda gauge, 50 ---- gauges, 203-206 Rohl river, 36 Rosaires, 13, 14, 44, 128 Rosetta branch, 14, 15, 33, 53, 60, 61, 85, 86, 87, 89, 139, 140 ---- ---- discharge table, 151 ---- ---- distances, 123 ---- ---- gauges, 207 ---- ---- velocities, 121 Ross, Col. Justin, 77 Rudolf, Lake, 16 Ruenzori, Mountain, 16, 21, 29 S Salaama river, 13, 45 Sandstone, Nubian, 24, 112, 114 Sayce, Rev., Professor, 79 Schweinfurth, Dr., 36, 39, 85 Scott-Moncrieff, Sir Colin, 3, 74 Scour and deposit of silt, 44, 92, 95, 99 Semliki river, 12, 29 Sennaar, 14, 44 Semna Cataract, 47 Sesostris, 66 Settit river, 13, 45 Silsila, 21, 74, 112 Slopes, 14, 47, 48, 49, 53, 120, 157 Sobat River, 12, 13, 15, 23, 35, 36, 37, 56, 61, 82, 84, 119, 129, 134, 139-141 ---- ---- discharge table, 145 ---- ---- gauges, 175, 176 ---- ---- slopes, 120 ---- ---- velocities, 121 ---- ---- tributaries, 37 Soil analysis, 45, 61, 63, 64, 100, 101 Sparkes, Col., 40 Speke and Grant, 11 Strabo, 78 Storage, see Projects Suakin-Khartoum railway, 100 Subject matter, 7, 8 Subsoil water, 63, 67 Sudan, 88, 100, 102, 103, 105, 106 Sudd region, 13, 16, 33, 34, 35, 37, 38, 39, 41, 56, 57, 58, 82, 83 T Temperatures, 19, 20, 21, 214-220 Tewfikieh, 41, 134, 139, 140, 141 ---- discharge table, 146 ---- gauge, 177 Thebes, 67 Tributaries of Lake Albert, 31 ---- ---- the Albert Nile, 31, 32, 34 ---- ---- ---- Atbara, 45 ---- ---- ---- Blue Nile, 44 ---- ---- ---- Lake Edward, 29 ---- ---- ---- Gazelle river, 36 ---- ---- ---- Sobat river, 36 ---- ---- ---- Lake Victoria, 28 ---- ---- ---- Victoria Nile, 29 Trough of the Nile, cubic contents, 155 Tsana Lake, 13, 15, 43, 45, 88, 103, 129 Tumat river, 44 U Uganda, 29, 130 V