Near the middle of Lake Victoria is a small island called Godsiba, or abuyongo. It was the site of a naval action in the first world war, a rather comic affair between German and British lake steamers. This little island was not visited after that action until 1927, when I was one of a small party which landed there and examined it. We found it very cut off from the world and all the young people were brought along to see our white faces. The island contained however quite a flourishing little community of fishermen and cultivators. After that visit Godsiba was left to itself for another twenty years or so, but was visited again last year, when the Provincial Commissioner and two of our Lake Victoria Fisheries Officers landed there and had another look around. They reported that no significant change had taken place, and another generation of the islanders saw white faces for the first time. Now Godsiba Island is a very unimportant part of East Africa, but I mention it as one of the few places which has not yet come into contact with European ideas. If Godsiba is left to itself for another twenty years, its little community would make a most interesting study in comparative geography and sociology. The changes which will by then have taken place in most of the neighbouring lands will be considerable, but Godsiba will still have its self-contained and self administered community of the old Africa. Changing our perspective from this little island to the whole political region of British East Africa (Kenya, Tanganyika, Uganda and Zanzibar), we perceive at once the unfortunate fact, arising from its historical geography, that the boundaries, whether of countries, provinces, districts, or even farms, so often run along drainage lines rather than along watersheds. Admittedly boundaries sometimes have no physiographic significance, having been defined as straight lines between points, as in part of the frontier between Italian Somaliland and Kenya; but in most cases where they follow a geo? graphic feature it is a drainage line. For the external boundary of the region there is a reach of the Daua river, a reach of the Nile near Nimule, a central line down Lake Albert, the Semliki river, Lake Edward, Lake Tanganyika and finally the Ruvuma river. At but few points do watersheds or mountains form the boundary; part of the Imatong mountains to the north of Uganda, a little stretch of the Nile-Congo watershed along the West Nile district of Uganda, Mts. Ruwenzori, Sabinyo and Muhavura, and a portion of the divide between the Luapula and Lake Rukwa drainage areas. It is obvious why it came about that frontiers in Africa, as elsewhere, were so often defined as drainage lines. They had to be laid down when there was little knowledge about the country and few maps of any accuracy. It was necessary to define frontiers with reference to obvious features on the ground, and a lake or a river is a much more obvious feature than a watershed. It is