Leaving Kota-kota Bay, we turned away due West on the great slave route to Katanga's and Cazembe's country in Londa. Juma lent us his servant, Selele, to lead us the first day's march. He said that the traders from Kilwa and Iboe cross the Lake either at this bay, or at Tsenga, or at the southern end of the Lake; and that wherever they may cross they all go by this path to the interior. They have slaves with them to carry their goods, and when they reach a spot where they can easily buy others, they settle down and begin the traffic, and at once cultivate grain. So much of the land lies waste, that no objection is ever made to any one taking possession of as much as he needs; they can purchase a field of cassava for their present wants for very little, and they continue trading in the country for two or three years, and giving what weight their muskets possess to the chief who is most liberal to them. The first day's march led us over a rich, well-cultivated plain. This was succeeded by highlands, undulating, stony, and covered with scraggy trees. Many banks of well rounded shingle appear. The disintegration of the rocks, now going on, does not round off the angles; they are split up by the heat and cold into angular fragments. On these high downs we crossed the River Kaombe. Beyond it we came among the upland vegetation--rhododendrons, proteas, the masuko, and molompi. At the foot of the hill, Kasuko-suko, we found the River Bua running north to join the Kaombe. We had to go a mile out of our way for a ford; the stream is deep enough in parts for hippopotami. The various streams not previously noticed, crossed in this journey, had before this led us to the conclusion, independently of the testimony of the natives, that no large river ran into the north end of the Lake. No such affluent was needed to account for the Shire's perennial flow.