The springboard
The explorers' journey began on the island of Zanzibar, at the time the centre of the East African slave trade and the springboard for all expeditions to the interior of Africa. Burton and Speke spent six months in Zanzibar port, the Arab flavour of which was decidedly to the eclectic taste of Burton, who spent his time learning Swahili and measuring the size of the male inhabitants' penises, an anthropological pursuit calculated to unsettle the prudish Speke.
On 16 June 1857, Burton and Speke set sail for the mainland in a naval vessel loaned by the sultan of Zanzibar. From Bagamoyo, now in Tanzania, their caravan marched into the interior. Niggling friction between Burton and Speke was already surfacing. The latter wrote: 'Captain Burton, being no sportsman, would not stop for shooting.'
After five months' journey, the party straggled into Tabora, 600 miles from the coast, a settlement founded by Arab traders as a base for slave traffic. Here, Burton heard that somewhere to the west lay a 'slug-like lake' of enormous size that he guessed might be the legendary tears of Isis, said by the ancient Egyptians to be the source of the Nile.
A terrible journey
In December, Burton and Speke set out with a new caravan and crossed the hills of Unyamwezi, finally sighting the lake - Tanganyika - in February 1858. This, in itself, was a great triumph - it would later become known that this large body of water was the source of the Congo river.
By now, both men were unable to walk, Speke was suffering from eye problems and Burton had an ulcerated jaw. Making camp at Ujiji - a site that would later become famous as the meeting place of explorers Stanley and Livingstone - Burton discovered from informants that a river, the Rusizi, flowed out of the lake to the north. This, he surmised, might be the headwaters of the Nile. Burton, still disabled, hired two dug-out canoes and, after a long and terrible journey, made it to the river, only to discover that the Rusizi flowed into, and not out of, the lake.
Burton and Speke left Ujiji the following May and arrived back in Tabora some weeks later. It was here that the great falling out between them began. Burton's Arab informants explained that, about two weeks' march to the north, lay a lake that was far bigger than Tanganyika. Speke later claimed that he had urged Burton to investigate this lead but the latter had refused, so Speke set off alone. Burton, however, argued that, although he had immediately realised the significance of the information, he had seen no reason why both explorers should go; still being lame himself, he had sent Speke to reconnoitre.
On Speke's return, he claimed that the lake to the north, which he had named Victoria, was the true source of the Nile. He later wrote: 'Captain Burton greeted me on arrival ... I ... expressed my regret that he did not accompany me as I felt quite certain in my mind that I had discovered the source of the Nile. This he naturally objected to, even after hearing all my reasons for saying so, and therefore the subject was dropped.' But it should be remembered that Speke's claim was based only on his belief in it - he had stayed at Lake Victoria for only three days and had seen just a tiny section of the southern shore.
Out in the cold
From this moment, Burton focused on Lake Tanganyika, and Speke on Lake Victoria, as the source of the Nile. Each was impervious to any other arguments. Their quarrel may seem absurd, but it is as well to remember that they had lived cheek by jowl in the most difficult and dangerous circumstances for well over a year. Just as they had begun to get on each other's nerves, they disagreed about the issue that lay at the heart of the entire undertaking. Speke later wrote to the secretary of the Royal Geographical Society: 'B. is one of those people who never can be wrong, and will never acknowledge an error, so that, when only two are together, talking becomes more of a bore than a pleasure.'
The party set off on the return journey at the end of September 1858. Burton and Speke collapsed almost at once and had to be carried. When they reached Zanzibar, the two men were outwardly still friends. In mid-April 1859, Speke left for England while Burton convalesced in Aden (now Yemen) at the entrance to the Red Sea. According to Burton, Speke's last words before he embarked on HMS Furious contained a promise that he would await his companion's arrival in London before revealing the results of the expedition.
When the haggard Burton arrived in London on 21 May, he found that Speke had not remained silent and that his claim had been accepted by the Royal Geographical Society. Moreover, the society had already commissioned Speke to lead a new expedition to bring back proof that Lake Victoria was the source of the Nile.
An accident?
Speke's second expedition, however, did not return with incontrovertible proof that his claim was correct, and Burton continued to advance his own for Lake Tanganyika. In 1863, a special meeting of several hundred geographers and scientists of the British Association for the Advancement of Science was convened in Bath to hear both cases and reach a final solution. However, on the day before he was due to address the association - and only hours after he and Burton had cut each other dead at a preliminary meeting in Bath - Speke, a crack shot, was killed in a hunting accident. It has been often suggested but never conclusively proven that, fearful of being worsted in a furious debate with the demonic Burton, Speke took his own life.
Burton was very badly affected by Speke's death. His wife Isabel later wrote that he 'wept long and bitterly' after hearing the news and that she was 'for many a day trying to comfort him'. It was not until 12 years later that the explorer and journalist Henry Morton Stanley proved that Speke's hunch had been right all along.
