Geographical Notes: The source of the Nile, I presume?

AT THE beginning of the 19th century, Europeans knew very little about Africa. In a remarkably short time, missionaries arrived. Then came explorers, who mapped rivers and mountains, and catalogued flora and fauna. These explorations paved the way for increasing European domination, until, 100 years later, the enormous continent was ruled by European powers.

By the end of the 20th century, Africa seems again a great unknown - a continent gripped by political turmoil, wrestling with huge economic and environmental challenges, and struggling to define itself and emerge from the long shadow cast by colonialism. The intricate origins of the Nile, the greatest of Africa's rivers, still intrigue us, invite study and compel awe.

The Nile is the longest river in the world: 6,695km long. From ancient times the fact that it flows through a desert, and that it floods annually, fascinated people. Where does all this water come from? Claudius Ptolemy, who lived in Alexandria in the second century AD, collected travellers' tales from which he constructed maps showing the whole of the known world. He correctly stated that the Nile flowed out of two or three great reservoirs located in a great ice-capped mountain range on the equator in the heart of Africa - the Mountains of the Moon. But confirming his data was no simple matter.

The Royal Geographical Society sent Richard Burton to investigate. But Burton never saw the source of the Nile. John Speke, on a side trip north from the town of Tabora, claimed to have seen a huge inland sea which he concluded must be the Nile's source and convinced the society that it should sponsor him to explore this lake and its connection to the Nile. He convinced James Grant to accompany him. Speke "discovered" the Victoria Nile and Ripon Falls, and had heard of yet another great lake which had something to do with the headwaters of the Nile. The round trip took two years, but they became the first Europeans to see Lake Albert.

In England during those two years, the disagreement between Burton and Speke about the source of the Nile had flared into a controversy. The afternoon before the two were to debate the matter in public, Speke died in a shooting accident. The RGS selected the most famous explorer of the day, Dr David Livingstone, to resolve the controversy and sponsored his third trip to Africa. Shortly after Livingstone started inland, he lost touch with the British authorities in Zanzibar and was rumoured to have died. James Gordon Bennett Jnr, the owner of The Herald newspaper, chose one of his reporters, Henry Morton Stanley, to find Livingstone. Stanley tracked down Livingstone, who had learned very little about the Nile's source in five years of effort and had shifted his attention from exploration to ways of combating slavery. The two quickly became friends and in a month they did more in terms of the Nile question than the doctor had managed to do on his own - they proved that the Ruzizi River flowed into the north end of Lake Tanganyika. Thus, the only possible connection between this lake and the Nile was the Lualaba River.

Stanley could not stay longer, but left Livingstone what supplies he could and sent more to him from Zanzibar. When he heard of Livingstone's death the next year, Stanley gained the support of two newspapers for an expedition to finish Livingstone's work. He circumnavigated Lake Victoria, he saw Lake Edward and he sailed down the Lualaba and proved that it was a tributary of the Congo River, not the Nile, by following it to its mouth on the Atlantic coast.

These were not the only Victorian explorers, but they were the ones whose work ultimately resulted in the mystery of the Nile's source being clearly articulated and eventually solved.

Christopher Ondaatje is the author of `Journey to the Source of the Nile' (HarperCollins, pounds 20)