For nine months of the year the winds blow from the South Atlantic along the course of the Congo, and up the Aruwimi. They bear the moisture of the sea, and the vapours exhaled by a course of 1400 miles of a river which spreads from half-a-mile to sixteen miles wide, and meeting on their easterly course the cold atmosphere prevailing at the high altitude they descend upon the forest almost every alternate day in copious showers of rain. This forest is also favourably situated to receive the vapours exhaled by Lakes Tanganika, the Albert Edward, and Albert Lakes. While standing in the plain on the verge of the forest, I have seen the two rain clouds, one from the westward and one from the eastward, collide and dissolve in a deluge of rain on Pisgah Mount and the surrounding country. Besides the rains, which lasted ten or twelve hours at a time during our march from Yambuya to Fort Bodo, we had frequent local showers of short duration. When these latter fell we were sure that some lofty hill was in the neighbourhood, which had intercepted a portion of the vapour drifting easterly, and liquified it for the benefit of the neighbourhood. The rear-guard of the caravan was sometimes plunged in misery by a heavy rainfall while the pioneers were enjoying the effects of sunshine above their heads. It occurred at Mabengu Rapids, and at Engweddé. Being in the depths of the forest we could not see any sign of a hill, but such sudden showers betrayed the presence of one in the vicinity. When well away from these localities we would sometimes look behind down a straight stretch of river, and hilly masses 500 feet above the river were revealed to us. [Illustration: A PAGE FROM MR. STANLEY’S NOTE-BOOK.] The Ituri or Upper Aruwimi is therefore seldom very low. We have seen it in July about six feet below high-water mark. In October one night it rose a foot; it is highest in November, and lowest in December. But it is a stream that constantly fluctuates, and pours an immense volume of water into the Congo. In length of course it is about 700 miles, rising to the south of that group of hills known as the Travellers’ Group, and called Mounts Speke, Schweinfurth, and Junker. Its basin covers an area of 67,000 square miles. On the north side of the basin we have heard of the Ababua, Mabodé, Momvu, and the Balessé, to the south are the Bakumu and Baburu. These are the principal tribes, which are subdivided into hundreds of smaller tribes. The language of the Bakumu which is to be found inland east of Stanley Falls, is known as far as Panga Falls, with slight dialectic variations among the Baburu. The language of Momvu is spoken between Panga Falls and the Ngaiyu. East of that we found that the language of the Balessé took us as far as Indenduru, beyond that was a separate and distinct language spoken by the Babusessé. But we found sub-tribes in each section who professed not to understand what was said to them from natives two camps removed from them.