as they were from fever, they found so difficult to surmount. But however savage in appearance, these uplands are at least favoured with a salubrious climate, and the Europeans enervated by a residence on the marshy plains of the seaboard might here establish health-resorts to recover their strength in an atmosphere resembling that of the temperate zone. Most of the Usagara villages are built above the river valleys on the advanced spurs of the main ranges.
River Systems
A few inconsiderable watercourses reach the coast north of the Rovuma estuary; but the first large fluvial delta is that of the Rufiji or Lufiji, which lies 180 miles beyond that point. This river does not flow from Lake Nyassa, as was reported to Livingstone by the natives; nevertheless its farthest headstreams have their sources to the west of this lacustrine basin, and its ramifying affluents drain a vast extent of land on both sides of the ranges skirting the plateau. The whole area of drainage comprises an area roughly estimated at 6,000 square miles. The Luwego, or Luvu (Lu-Wego, Lu-Vu), the chief southern tributary, has not yet been surveyed to its source. It is not navigable, and probably has its source in the Livingstone Mountains, flowing thence in a north-westerly direction to its junction with the Uranga (U-Ranga). This branch comes from the west, plunging from fall to fall in a rocky bed flanked by granite walls. But hundreds of canoes formed of single trunks of trees are met in the navigable reaches, which during the rainy season sometimes expand to a breadth of over 2,000 yards.
The united Luwego and Uranga take the name of Rufiji, which a few hundred yards below the confluence tumbles over the Shuguli Cascades, a series of falls and rapids skirted by granite cliffs. Above these cataracts some rocky islets in both converging branches serve as refuges for the natives exposed to the sudden attacks of marauders. Lower down the Rufiji continues the north-easterly course of the southern or Luwego branch, and offers at intervals a few navigable reaches, although in many places the canoes of the natives are arrested by rapids, reefs, and sandbanks. These obstructions grow more numerous as the mainstream approaches the confluence of the Ruaha (Rua-Ha), a large stream from the west, whose basin comprises a large tract of country between Urori and Ugogo. Like the Luwego, the Luaha is unnavigable, notwithstanding the large volume of water it rolls down during the rainy season, when it becomes the largest branch of the whole system. But during the period of drought it is a less copious stream than the Rufiji.
After its confluence with the Ruaha, the Rufiji receives no further contributions from any quarter; but before reaching the sea it has still to surmount the barrier presented by the most advanced ridge of the coast ranges. This ridge runs north and south athwart the course of the river, which pierces it at the gorge where it rushes over the Pangani Falls. No accurate measurement has yet been taken of the total incline at this point, but it must be very considerable, 117-AF
