n the coast. The slaves are either prisoners taken in war, or
children whom their parents have parted with in the hope of their being
carried to a more fertile country. For above ninety years after the first
discovery of this coast, the Portuguese merchants were accustomed to
enter the large rivers by which the country is everywhere intersected,
trading independently with the numerous tribes inhabiting their banks;
but now the whole of this commerce is in the hands of stationary licensed
factors, to whom it is farmed.

On quitting St Jago we steer southerly for the Rio Grande, which is on
the north of Ethiopia, beyond which we come to the high mountain of
Sierra Liona, the summit of which is continually enveloped in mist, out
of which thunder and lightning almost perpetually flashes, and is heard
at sea from the distance of forty or fifty miles. Though the sun is quite
vertical in passing over this mountain, and extremely hot, yet the thick
fog is never dissipated. In our voyage we never lose sight of land, yet
keep always at a considerable distance, carefully observing the
declination of the sun, and keeping a southerly course till we arrive in
_four degrees on the equinoctial_[7], when we suddenly change our course
to the south-east, keeping the Ethiopian coast always on our left hand in
our way to the island of St Thomas. On this coast, between the tropic and
the equinoctial, we never meet with any hard gales, as storms are very
rarely found within the tropics. On nearing the land, the soundings in
many parts of the coast do not exceed fifty _braccia_, but farther out
the depth rapidly increases, and the sea usually runs high at a distance
from the land. When we arrived at Rio del Oro, as mentioned before, we
observed four stars in the form of a cross, of an extraordinary size and
splendour, elevated thirty degrees above the antarctic pole, and forming
the constellation called _il Crusero_. While under the tropic of Cancer,
we saw this constellation very low; and, on directing our _balestra_[8]
to the lowermost of these stars, we found it to be directly south, and
concluded that it must be in the centre of the antarctic polar circle. We
observed the same constellation very high when we were at the island of
St Thomas; and remarked that the moon, after rain, produces a rainbow
similar to that occasioned by the sun during the day, except that the
colours were dim and ill-defined. On leaving the straits of Gibraltar, I
d