He was accepted for service
by the London Missionary Society, and in the year 1840 he sailed for
South Africa. After a voyage of three months he arrived at Cape Town
and made his way in a slow ox-waggon seven hundred miles to Kuruman,
a small mission station in the heart of Bechuanaland where Dr. Moffat
had laboured for twenty years. He did well, and two years later he
was sent north to form another mission station at Mabotsa (Transvaal).
Having married Moffat's daughter Mary, he worked in these parts till
June 1849, when, with his wife and three children, he started with
oxen and waggon for a journey northwards. Across the great Kalahari
Desert moved the exploring family, till they came to the river called
Zouga, which, said the natives, led to a large lake named Lake Ngami.
In native canoes, Livingstone and his little family ascended this
beautifully wooded river, "resembling the river Clyde above Glasgow,"
till on 1st August 1849, Lake Ngami appeared, "and for the first time,"
says Livingstone, "this fine sheet of water was beheld by Europeans."
The lake was two thousand eight hundred feet above the sea, but the
climate was terribly unhealthy. The children grew feverish, and
mosquitoes made life a misery to them, while the tsetse fly made further
exploration for the moment impossible. So the family journeyed back
to headquarters for a time. But Livingstone was unsatisfied, and once
more in 1851 we find him starting again with wife and children to seek
the great river Zambesi, known to exist in central Africa, though the
Portuguese maps represented it as rising far to the east of
Livingstone's discovery.

[Illustration: LIVINGSTONE, WITH HIS WIFE AND FAMILY, AT THE DISCOVERY
OF LAKE NGAMI. From Livingstone's _Missionary Travels_.]

"It was the end of June 1851," he tells us, "that we were rewarded
by the discovery of the Zambesi in the centre of the continent. This
was an important point, for that river was not previously known to
exist there at all. As we were the very first white men the inhabitants
had ever seen, we were visited by prodigious numbers of Makololo in
garments of blue, green, and red baize." Livingstone wanted to know
more of this unknown river, but he now decided that exploring with
a wife and family was not only perilous, but difficult, so he returned
to the coast, put them on a homeward-bound ship for England, and
returned to central Africa to continue his work of exploration alone.

It was 11th