ke them away.

Large columns of smoke rose daily from different points of the horizon,
showing that the natives were burning off the immense crops of tall
grass, here a nuisance, however valuable elsewhere. A white cloud was
often observed to rest on the head of the column, as if a current of hot
damp air was sent up by the heat of the flames and its moisture was
condensed at the top. Rain did not follow, though theorists have
imagined that in such cases it ought.

Large game, buffaloes, and zebras, were abundant abreast the island, but
no men could be seen. On the mainland, over on the right bank of the
river, we were amused by the eccentric gyrations and evolutions of flocks
of small seed-eating birds, who in their flight wheeled into compact
columns with such military precision as to give us the impression that
they must be guided by a leader, and all directed by the same signal.
Several other kinds of small birds now go in flocks, and among others the
large Senegal swallow. The presence of this bird, being clearly in a
state of migration from the north, while the common swallow of the
country, and the brown kite are away beyond the equator, leads to the
conjecture that there may be a double migration, namely, of birds from
torrid climates to the more temperate, as this now is, as well as from
severe winters to sunny regions; but this could not be verified by such
birds of passage as ourselves.

On reaching Mazaro, the mouth of a narrow creek which in floods
communicates with the Quillimane river, we found that the Portuguese were
at war with a half-caste named Mariano _alias_ Matakenya, from whom they
had generally fled, and who, having built a stockade near the mouth of
the Shire, owned all the country between that river and Mazaro. Mariano
was best known by his native name Matakenya, which in their tongue means
"trembling," or quivering as trees do in a storm. He was a keen slave-
hunter, and kept a large number of men, well armed with muskets. It is
an entire mistake to suppose that the slave trade is one of buying and
selling alone; or that engagements can be made with labourers in Africa
as they are in India; Mariano, like other Portuguese, had no labour to
spare. He had been in the habit of sending out armed parties on slave-
hunting forays among the helpless tribes to the north-east, and carrying
down the kidnapped victims in chains to Quillimane, where they were sold
by his brother-in-law Cruz Coim