The work of rediscovering the lakes was entrusted to a remarkable man named Richard Burton, a man whose love of adventure was well known. He had already shown his metal by entering Mecca disguised as a Persian, and disguised as an Arab he had entered Harar, a den of slave traders, the "Timbuktu of Eastern Africa." On his return he was attacked by the Somalis; one of his companions was killed, another, Speke, escaped with terrible spear-wounds, and he himself was badly wounded.

Such were the men who in 1856 were dispatched by the Royal Geographical Society for the exploration of the mysterious lakes in the heart of central Africa. Speke gives us an idea of the ignorance prevailing on this subject only fifty-six years ago: "On the walls of the Society's rooms there hung a large diagram constructed by two missionaries carrying on their duties at Zanzibar. In this section map, swallowing up about half of the whole area of the ground included in it, there figured a lake of such portentous size and such unseemly shape, representing a gigantic slug, that everybody who looked at it incredulously laughed and shook his head—a single sheet of sweet water, upwards of eight hundred miles long by three hundred broad, equal in size to the great salt Caspian."

It was April 1857 before Burton and Speke had collected an escort and guides at Zanzibar, the great slave market of East Africa, and were ready to start for the interior. "We could obtain no useful information from the European merchants of Zanzibar, who are mostly ignorant of everything beyond the island," Burke wrote home on 22nd April.

At last on 27th June, with thirty-six men and thirty donkeys, the party set out for the great malarious coast-belt which had to be crossed before Kaze, some five hundred miles distant, could be reached. After three months' arduous travelling—both Burton and Speke were badly stricken with fever—they reached Kaze. Speke now spread open the map of the missionaries and inquired of the natives where the enormous lake was to be found. To their intense surprise they found the missionaries had run three lakes into one, and the three lakes were Lake Nyassa, Tanganyika, and Victoria Nyanza. They stayed over a month at Kaze, till Burton seemed at the point of death, and Speke had him carried out of the unhealthy town. It was January before they made a start and continued their journey westward to Ugyi.

"It is a wonderful thing," says Drummond, "to start from the civilisation of Europe, pass up these mighty rivers, and work your way alone and on foot, mile after mile, month after month, among strange birds and beasts and plants and insects, meeting tribes which have no name, speaking tongues which no man can interpret, till you have reached its sacred heart and stood where white man has never trod before."

As the two men tramped on, the streams began to drain to the west and the land grew more fertile, till one hundred and fifty miles from Kaze they began to ascend the slope of mountains overhanging the northern half of Lake Tanganyika. "This mountain mass," says Speke, "I consider to be the True Mountains of the Moon." From the top of the mountains the lovely Tanganyika Lake could be seen in all its glory by Burton. But to Speke it was a mere mist. The glare of the sun and oft-repeated fever had begun to tell on him, and a kind of inflammation had produced almost total blindness. But they had reached the lake and they felt sure they had found the source of the Nile. It was a great day when Speke crossed the lake in a long canoe hollowed out of the trunk of a tree and manned by twenty native savages under the command of a captain in a "goatskin uniform." On the far side they encamped on the opposite shore, Speke being the first white man to cross the lake.

Having retired to his hut for the night, Speke proceeded to light a candle and arrange his baggage, when to his horror he found the whole interior swarming with black beetles. Tired of trying to brush them away, he put out his light and, though they crawled up his sleeves and down his back, he fell asleep. Suddenly he woke to find one crawling into his ear, and in spite of his frantic efforts it crept in farther and farther till it reached the drum, which caused the tired explorer intense agony. Inflammation ensued, his face became drawn, he could with difficulty swallow a little broth, and he was quite deaf. He returned across the lake to find his companion, Burton, still very ill and unfit for further exploration.

So Speke, although still suffering from his ear, started off again, leaving Burton behind, to find the great northern lake spoken of as the sea of Ukerewe, where the Arabs traded largely in ivory. There was a great empire beyond the lake, they told him, called Uganda.

But it was July 1858 when the caravan was ready to start from Kaze. Speke himself carried Burton's large elephant gun. "I commenced the journey," he says, "at 6 p.m., as soon as the two donkeys I took with me to ride were caught and saddled. It was a dreary beginning. The escort who accompanied me were sullen in their manner and walked with heavy gait and downcast countenance. The nature of the track increased the general gloom.

"For several weeks the caravan moved forward, till on 3rd August it began to wind up a long but gradually inclined hill, until it reached its summit, when the vast expanse of the pale blue waters of the Nyanza burst suddenly upon my eyes! It was early morning. The distant sea-line of the north horizon was defined in the calm atmosphere, but I could get no idea of the breadth of the lake, as an archipelago of islands, each consisting of a single hill rising to a height of two or three hundred feet above the water, intersected the line of vision to the left. A sheet of water extended far away to the eastward. The view was one which even in a well-known country would have arrested the traveller by its peaceful beauty. But the pleasure of the mere view vanished in the presence of those more intense emotions called up by the geographical importance of the scene before me. I no longer felt any doubt that the lake at my feet gave birth to that interesting river (Nile), the source of which has been the subject of so much speculation and the object of so many explorers. This is a far more extensive lake than Tanganyika; it is so broad that you could not see across it, and so long that nobody knew its length. This magnificent sheet of water I have ventured to name Victoria after our gracious sovereign."

Speke returned to Kaze after his six weeks' eventful journey, having tramped no less than four hundred and fifty-two miles. He received a warm welcome from Burton, who had been very uneasy about his safety, for rumours of civil war had reached him. "I laughed over the matter," says Speke, "but expressed my regret that he did not accompany me, as I felt quite certain in my mind I had discovered the source of the Nile."

Together the two explorers now made their way to the coast and crossed to Aden, where Burton, still weak and ill, decided to remain for a little, while Speke took passage in a passing ship for home.

When he showed his map of Tanganyika and Victoria Nyanza to the President of the Royal Geographical Society in London, Sir Roderick Murchison was delighted.

"Speke, we must send you there again," he said enthusiastically.

And the expedition was regarded as "one of the most notable discoveries in the annals of African discovery."