_Feb. 1._—On the 1st of February, after a very necessary halt of two days at Mgongo Tembo, with an addition to our force of eight pagazis and two guides, and encouraged by favourable reports of the country in front, we entered Mangura in Usukuma near a strange valley which contained a forest of borassus palms. In the beds of the several streams we crossed this day we observed granite boulders, blue shale, basalt, porphyry and quartz. Beyond Mangura, or about six miles west of it, was situate Igira, a sparse settlement overlooking the magnificent plain of Luwamberri, at an altitude by boiling-point of 5350 feet. A camp which we established in this plain, was ascertained with the same apparatus to be 4475 feet. Ten miles farther, near a sluggish ditch-like creek, the boiling-point showed 4250 feet, only 100 feet higher than Lake Victoria. As far as Igira the myombo flourished, but when we descended into the plain, and the elevation above the sea decreased to 4000 feet, we discovered that the baobab became the principal feature of the vegetation, giving place soon after to thorny acacias and a variety of scrub, succeeded in their turn by a vast expanse of tawny grass. The Luwamberri plain—with its breadth of nearly forty miles, its indefinite length of level reach towards the N.N.W., its low altitude above the Victorian Lake, the wave-worn slopes of the higher elevations which hem it on the east and the south—appears to me to have been in ancient times a long arm of the great lake which was our prospective goal at this period. About sixteen miles from Igira there is a small sluggish stream with an almost imperceptible current northward, but though it was insignificant at the time of our crossing, there were certain traces on the tall grass to show that during the middle of the rainy season it is nearly a mile broad, and very deep. Several nullahs or ravines with stagnant water, when followed up, prove to have their exit in the broad channel. In the centre of the level plain rises a curious elevation, like an island crowned with a grove, whither the game with which the plain teems resort during the wet season. At the period of our crossing, however, they roved in countless numbers over the plain—giraffe, zebra, gnu, buffalo, springbok, water-buck, kudu, hartebeest, wild-boar, and several varieties of smaller antelope; while birds abounded, ibis, field-larks, fish-hawks, kingfishers, spur-winged geese, ducks, vultures, flamingoes, spoonbills, and cranes.