Sir Samuel and Florence Baker on the cliff above Lake Albert

Some discoveries are made by the man who first sees a thing, and some by the man who first writes it down. The Nile had been a question for two thousand years before a Norfolk hunter and his Transylvanian wife stood on a ridge of red earth above a lake the Banyoro had fished since memory began, and named it for a German prince dead three winters in Windsor. The water did not change. The map did.

THE LONG APPROACH

Samuel White Baker, born in Enfield on the eighth of June 1821 into a London merchant family, had been many things before he became an explorer: a coffee planter at Newera Eliya in Ceylon for nine years, a widower at thirty-four, a road-builder on the Danube, a hunter of elephant and buffalo. He was a large-boned, bearded, plain-spoken Englishman who trusted a rifle and his own eye and was bored by drawing-rooms. At the slave-market at Vidin on the lower Danube, in the spring of 1859, he had paid for a fair-haired Hungarian orphan of seventeen named Florence Maria Finnian von Sass, taken her out of the bidding, and never been parted from her since. She rode as he rode, shot as he shot, learned Arabic as he did, and went into Africa in his shadow because the alternative was to be left behind in Cairo, and neither of them could bear that.

Behind them in 1864 lay four years of the Nile question at its loudest. Burton and Speke had quarrelled their way back from Tanganyika in 1858. Speke had gone again with Grant and come down from the north shore of a great lake he called Victoria in 1862, swearing it was the source. The Royal Geographical Society in Savile Row was divided, and Burton was waiting in London with a knife. The Bakers, unofficial, unsalaried, and answerable to no committee, had set out from Cairo in April 1861 to push up the White Nile themselves and meet Speke coming down. They had wintered in the Bahr-el-Jebel marshes among the Dinka, crossed the Acholi country on foot when their boats failed, and been kept eight weeks at the court of King Kamurasi of Bunyoro, who wanted Florence as a gift before he would let them pass. Sam had refused with his hand on his revolver and Florence at his shoulder, and Kamurasi had laughed and let them go.

THE MORNING OF THE FOURTEENTH

On the night of the thirteenth of March 1864 they slept at the Banyoro fishing village of Vacovia, on the lip of the western escarpment of what would later be called the Albertine Rift. They were both ill. Sam had been carried the last days in a litter by Kamurasi's bearers; Florence had walked out of a coma at Shooa only a few weeks earlier, having lain three days insensible while he dug what he believed would be her grave. They were thin, fevered, and almost out of beads and cloth to pay their way home.

The morning came hazy, in the equatorial dry-season light that flattens distance. They climbed the slope above the village before the heat. The ground was red, friable, broken with thorn. Sam went first with his telescope. Florence behind him in a man's shirt and trousers, her hair cropped short against fever. Below them, when the ridge fell away, the land fell with it: a long pale drop of two thousand feet, and at the bottom of the drop a sheet of water running north and south as far as the eye could carry, the far shore on the Congolese side faint as a pencil line at fifty miles. Papyrus rafts of fishermen lay scattered on the surface like seed on a floor.

THE SECOND ON THE ESCARPMENT

He stood and looked. He had wanted this water for four years, and now that it was beneath him he found, as men do at the hinge of their lives, that the wanting and the having were not the same shape. The lake was larger than he had been told and smaller than Victoria. It ran the wrong way for the orthodoxy Burton was defending in London and the right way for the orthodoxy Speke had died defending only six months before, shot accidentally on a Wiltshire stile the previous September. He thought of Speke in that second, of the man whose claim he was about to second and complete; thought of the Royal Geographical medal that would now have to be divided; thought, with the particular sobriety of a man who has carried his wife through three years of swamp, that they would both go home alive after all. He turned and looked at Florence. She had taken off her hat. She was crying without sound, which was not her habit. He took her hand. The lake below them did not move. He wrote that evening, in the journal which became The Albert N'yanza, Great Basin of the Nile (1866), that the view was a grand expanse of water, a boundless sea horizon on the south and south-west, glittering in the noonday sun, and that he fell on his knees and thanked God that He had guided and supported us through all dangers to the good end. He named the lake, in the same entry, for the Prince Consort, dead at Windsor on the fourteenth of December 1861. Speke had given Victoria her living name in 1862. Baker gave Albert his posthumous one.

DOWN TO THE WATER

They went down the escarpment that afternoon by a goat-track, slipping, holding to each other's belts. At the shore he waded in to his waist in the warm fresh water and drank from his cupped hands, in the way men do who have crossed a desert to find a thing. The Banyoro fishermen who watched him from their papyrus rafts called the water Mwitanzige, the killer of locusts, because the swarms that crossed it fell exhausted into the lake. He wrote that name down too, before he wrote down Albert.

THE INTERLUDE OF KAMURASI

At Mruli, the river-station where they had left Kamurasi, the king was already calculating what the Englishman's lake would cost him. The Bunyoro kingdom had stood between the Nile and the inland trade for two centuries; a named European lake on a Geographical Society map meant steamers, then commissioners, then troops. Kamurasi did not live to see it. His son Kabarega would meet the consequence in person when Sam Baker himself, ten years later, came back up the river in the uniform of the Khedive of Egypt to annex the country. The hinge that opened in March 1864 closed on Bunyoro in 1872.

THE ROOM IN SAVILE ROW

They came out by the way they had gone in: Bunyoro, Acholi, the Lado reach, Gondokoro, the long boat down to Khartoum, Cairo by the spring of 1865. In London the Royal Geographical Society awarded him its Founder's Medal that May. He was knighted at Windsor on the twenty-third of August 1866. Florence, by then Lady Baker on the patent, was never received at Court. The Queen had been told the story of Vidin, and the Queen, who had loved one husband and would mourn him forty years, could not bring herself to receive a woman bought at a slave-market by another. Sam wrote to his sister that he did not give a damn for the drawing-rooms of Belgravia, and meant it. They went out again together to the Khedive Ismail in 1869, he as Pasha and Governor-General of the Equatorial Province, she riding beside him in the saddle, and spent four years burning slave-dhows on the upper river before coming home for good.

THE LONG WATER

He died at Sandford Orleigh in Devon on the thirtieth of December 1893, aged seventy-two, in the chair beside his library fire. Florence outlived him by twenty-two years and was buried beside him at Grimley in Worcestershire on the eleventh of March 1916, aged seventy-four, three days off the fifty-second anniversary of the morning above Vacovia. The lake they named is still on the map, the border between Uganda and the Democratic Republic of the Congo running down the middle of it. The Banyoro fishermen still put out papyrus rafts at dawn, and the locusts still fall, and the water is still called Mwitanzige by the people who live on its shore. A name written in a journal in March 1864 sits on top of an older one, the way a hand rests on another hand. Both are there. Some discoveries leave the world unchanged and only rearrange the words we have for it. The Bakers stood on a ridge above a lake that did not need them, and went home with a sentence that the world afterwards used to find it.