ivory and slaves are all that
Casembe ever can have to sell. About a month to the west of this
the people of Katanga smelt copper-ore (malachite) into large
bars shaped like the capital letter I. They may be met with of
from 50 lbs. to 100 lbs., weight all over the country, and the
inhabitants draw the copper into wire for armlets and leglets.
Gold is also found at Katanga, and specimens were lately sent
to the Sultan of Zanzibar.

As we come down from the watershed towards Tanganyika we enter an
area of the earth's surface still disturbed by internal igneous
action. A hot fountain in the country of Nsama is often used to
boil cassava and maize. Earthquakes are by no means rare. We
experienced the shock of one while at Chitimba's village, and
they extend as far as Casembe's. I felt as if afloat, and as huts
would not fall there was no sense of danger; some of them that
happened at night set the fowls a cackling. The most remarkable
effect of this one was that it changed the rates of the
chronometers; no rain fell after it. No one had access to the
chronometers but myself, and, as I never heard of this effect
before, I may mention that one which lost with great regularity
1.5 sec. daily, lost 15 sec.; another; whose rate since leaving
the coast was 15 sec., lost 40 sec.; and a third, which gained 6
sec. daily, stopped altogether. Some of Nsama's people ascribed
the earthquakes to the hot fountain, because it showed unusual
commotion on these occasions; another hot fountain exists near
Tanganyika than Nsama's, and we passed one on the shores of
Moero.

We could not understand why the natives called Moero much larger
than Tanganyika till we saw both. The greater Lake lies in a
comparatively narrow trough, with highland on each side, which
is always visible; but when we look at Moero, to the south of
the mountains of Rua on the west, we have nothing but an
apparently boundless sea horizon. The Luapula and Rovukwe form a
marsh at the southern extremity, and Casembe dissuaded me from
entering it, but sent a man to guide me to different points of
Moero further down. From the heights at which the southern
portions were seen, it must be from forty to sixty miles broad.
From the south end of the mountains of Rua (9 deg. 4' south lat.) it
is thirty-three miles broad. No native