9. =Lake Victoria Nyanza.=--Lake Victoria, the true source of the Nile, lies on the Equator, and fed by abundant rains and numerous streams, discharges its surplus waters over the Ripon Falls, and gives birth to the Victoria Nile. Its most important feeder, the Kagera, whose southernmost tributary rises in the Kangosi hills 2000 metres above sea level in south latitude 4°, has a length of some 600 kilometres. The direct line across the lake from the mouth of the Kagera to the Ripon Falls is 220 kilometres, so that in academical language the length of the Nile at the Ripon Falls is already 820 kilometres. Lake Victoria lies 1129 metres above sea level, and has an area of 60,000 square kilometres; though until the parallels of longitudes are definitely settled, the lake may be credited with an area of between 60,000 and 65,000 square kilometres, constituting it the largest fresh water lake in the old world. Its waters are beautifully clear and perfectly sweet. The depth of the lake is not great and it is covered with many islands. The greatest depth found by Commander Whitehouse in the northern half of the lake has been 73 metres, while the bays are shallow. The northern, southern and eastern shores of the lake, as described by Sir William Garstin, are generally clear, while the western shore, especially at the mouth of the Kagera, is flat, marshy and covered with papyrus. The country surrounding the lake is undulating or hilly and rises to a height of 700 metres above the lake at the south-east corner. The rocks are generally granites, chrystalline schists and quartzites, etc. The hills are covered with red clay and marl on the higher lands, while the valleys consist of a rich black loam.