Has it ever occurred to you that every river has a source—that every river begins somewhere, in a tiny spring? Few forms of exploration are more interesting than to trace a stream back to its first drop. The Thames, for example, begins in the Cotswold Hills—the merest little trickle. All running water, you know, sooner or later reaches the sea. That little trickle in the Cotswolds will in time glide past Henley and Hampton Court and Westminster Bridge, and past the Tower, and help to bear up the thousands of vessels in the Port of London, and at last will run out into the sea at Gravesend. Some day perhaps you will walk up the banks of the Upper Thames until you come to the Cotswold spring.

But of course a river, although we speak of its having one source, has others too. Many streams run into the Thames, and each of these has also its source. There is one, indeed, close to Speke’s monument—the Westbourne, which gives its name to Westbourne Grove, where Whiteley’s is. The West Bourne, like all the little London rivers, now runs underground, but it used to be open a hundred and more years ago. The West Bourne rises near the Finchley Road Station, and has many adventures before it reaches the Thames and the sea. It runs, I have been told, under the Bayswater Road into the Serpentine. At the bottom of the Serpentine it comes out again in a waterfall, where the rabbits are, and again runs underground to the King’s garden at the back of Buckingham Palace, where it reappears as a beautiful lake. Then it dives under the Palace and comes up again as the water in St. James’s Park, where all the interesting water-fowl live and have nests on an island—the ducks and gulls and cormorants and penguins. Then, once more, it disappears, this time under the Horse Guards and Whitehall, and comes out into the Thames. Not a bad career for a little bit of a stream rising at Hampstead, is it?

To explore that stream would be fairly easy, and it is not difficult to explore the Thames. But in order to realize quite what Speke did you must think for a moment of what it means to travel in unexplored countries. There are no maps: you have no notion what is before you; the natives may be suspicious of you and make war at once, or they may at first pretend to be friendly and then suddenly attempt a massacre; fever is always on your track; wild beasts may be in such numbers as to be a continual danger. It is a great thing to dare all these known and unknown perils just to do—what? To make a fortune? No. To add a country to England’s possessions? No. But just to gain a little more knowledge of geography; just to add one more fact to the world’s sum.

Illness came to both explorers, and they endured very severe privations, and at last Burton had to give up and allow Speke to go on alone. They parted at Kazé on July 9, 1858, just fifty years ago, Speke setting out with thirty-five native followers and supplies for six weeks. On August 3 he discovered a gigantic lake, to which he gave the name Victoria Nyanza—Victoria after his Queen, and Nyanza meaning a piece of water.

You should now get your atlas and look for the Nile and Kazé and the vast lake, where, as Speke then thought, and as is now known, the river Nile begins its course of three thousand four hundred miles, which does not end until, after passing through Khartoum, and Dongola, and Wady Halfa, and Assouan, and Thebes, and Ghizeh, and Cairo, it glides into the sea by the many mouths of its delta at Rosetta and Damietta and Alexandria.

Speke then returned to England, to tell his countrymen all about his discovery, and in 1860 he set out for Africa again, and began a series of very tedious and harassing marches from Zanzibar through Uganda to reach Victoria Nyanza once more, and explore it thoroughly. Illness again interrupted him, and the native kings were not wholly friendly, but at last, on July 28, 1862, he came to the head of the lake where the water that becomes the Nile tumbles over the edge of a cataract. This cataract he named Ripon Falls.

Speke telegraphed his news to England directly he reached a civilized town, so that when he himself landed at Southampton, in 1863, he was received as a hero, and honours were showered upon him, and he was the most famous traveller of his own or almost any other day.

Not every one, however (including Burton), was satisfied that the Nile really began at Ripon Falls, and books were written by Burton and others in support of rival theories. Speke, who naturally believed himself to be right, arranged to meet some of these other geographers in a public discussion at Bath, in September, 1864; but on the very morning of that day, as he was out partridge-shooting, he accidentally shot himself and died at the early age of thirty-seven.

Isn’t that a wretched way for a man to die after braving all the perils of unknown Africa?

And now, whenever you see the Speke monument again you will think of that great inland sea in Africa called Victoria Nyanza, and the Nile tumbling out of it and beginning its wonderful journey to the Mediterranean.