Zungomero, the head of the great river-valley, is a plain of black earth and sand, prodigiously fertile. It is enclosed on all sides except the eastern, or the line of drainage; northwards rise the peaks of Dut’humi; westwards lie the little Wigo hills and the other spurs of Usagara, uncultivated and uninhabited, though the country is populous up to their feet; and southwards are detached cones of similar formation, steep, rocky, and densely wooded. The sea-breeze is here strong, but beyond its influence the atmosphere is sultry and oppressive; owing to maritime influences the kosi, or south-west wind, sometimes continues till the end of July. The normal day, which varies little throughout the year, begins with the light milky mist which forms the cloud-ring; by degrees nimbi and cumuli come up from the east, investing the heights of Dut’humi, and, when showers are imminent, a heavy line of stratus bisects the highlands and overlies the surface of the plain. At the epochs of the lunar change rain falls once or twice during the day and night, and, when the clouds burst, a fiery sun sucks up poison from the earth’s putridity. The early nights are oppressive, and towards the dawn condensation causes a copious deposit of heavy dew, which even the people of the country dread. A prolonged halt causes general sickness amongst the porters and slaves of a caravan. The humidity of the atmosphere corrodes everything with which it comes in contact; the springs of powder-flasks exposed to the damp snap like toasted quills; clothes feel limp and damp; paper, becoming soft and soppy by the loss of glazing, acts as a blotter; boots, books, and botanical collections are blackened; metals are ever rusty; the best percussion caps, though labelled waterproof, will not detonate unless carefully stowed away in waxed cloth and tin boxes; gunpowder, if not kept from the air, refuses to ignite; and wood becomes covered with mildew. We had an abundance of common German phosphor-matches, and the best English wax lucifers; both, however, became equally unserviceable, the heads shrank and sprang off at the least touch, and the boxes frequently became a mere mass of paste. To future travellers I should recommend the “good old plan;” a bit of phosphorus in a little phial half full of olive oil, which serves for light as well as ignition. When accompanied by matchlock-men, however, there is no difficulty about fire; their pouches always contain a steel and flint, and a store of cotton, or of the wild Bombex, dipped in saltpetre or gunpowder solution.