great numbers of tribes which pass under
the general term Maravi. To the northeast there are extensive plains
destitute of trees, but covered with grass, and in some places it is
marshy. The whole of the country to the north of the Zambesi is asserted
to be very much more fertile than that to the south. The Maravi, for
instance, raise sweet potatoes of immense size, but when these are
planted on the southern bank they soon degenerate. The root of this
plant ('Convolvulus batata') does not keep more than two or three days,
unless it is cut into thin slices and dried in the sun, but the Maravi
manage to preserve them for months by digging a pit and burying them
therein inclosed in wood-ashes. Unfortunately, the Maravi, and all the
tribes on that side of the country, are at enmity with the Portuguese,
and, as they practice night attacks in their warfare, it is dangerous to
travel among them.

29TH. I was most sincerely thankful to find myself on the south bank of
the Zambesi, and, having nothing else, I sent back one of my two spoons
and a shirt as a thank-offering to Mpende. The different head men along
this river act very much in concert, and if one refuses passage they all
do, uttering the sage remark, "If so-and-so did not lend his canoes, he
must have had some good reason." The next island we came to was that
of a man named Mozinkwa. Here we were detained some days by continuous
rains, and thought we observed the confirmation of the Bakwain theory of
rains. A double tier of clouds floated quickly away to the west, and
as soon as they began to come in an opposite direction the rains poured
down. The inhabitants who live in a dry region like that of Kolobeng are
nearly all as weather-wise as the rain-makers, and any one living among
them for any length of time becomes as much interested in the motions of
the clouds as they are themselves. Mr. Moffat, who was as sorely tried
by droughts as we were, and had his attention directed in the same way,
has noted the curious phenomenon of thunder without clouds. Mrs. L.
heard it once, but I never had that good fortune. It is worth the
attention of the observant. Humboldt has seen rain without clouds, a
phenomenon quite as singular. I have been in the vicinity of the fall of
three aerolites, none of which I could afterward discover. One fell into
the lake Kumadau with a report somewhat like a sharp peal of thunder.
The women of the Bakurutse villages there all uttered a scream on