Don Henry of Portugal,
informs us in his preface, that he was the first navigator from the
_noble city of Venice_, who had sailed on the ocean beyond the Straits of
Gibraltar, to the southern parts of Negroland, and Lower Ethiopia. These
voyages at Cada Mosto are the oldest extant in the form of a regular
journal, and were originally composed in Italian, and first printed at
Venice in 1507. This first edition is now exceedingly scarce, but there
is a copy in the kings library, and another in the valuable collection
made by Mr Dalrymple. These voyages were afterward published by Ramusio
in 1613, and by Grynaeus in Latin. The latter was misled in regard to the
date; which he has inadvertently placed in 1504, after the death of
Prince Henry, and even subsequent to the discovery of the Cape of Good
Hope by Bernal Diaz. Even Ramusio, in his introduction to the voyages of
Cada Mosto, has made a mistake in saying that they were undertaken by the
orders of John king of Portugal, who died in 1433.

Ramusio imagined that the discoveries of Cada Mosto might tend to great
importance, as he considered the rivers Senegal and Rio Grande to be
branches of the Niger, by which means the Europeans might open a trade
with the rich kingdoms of Tombuto and Melli on that river, and thus bring
gold from the countries of the Negroes, by an easier, safer, and more
expeditious manner, than as conveyed by the Moors of Barbary by land,
over the vast and dangerous deserts that intervene between the country on
the Niger and Senegal rivers, and Barbary. As, by the account of Leo,
salt is the most valuable commodity throughout the countries of the
Negroes, Ramusio proposed that the ships should take in cargoes of salt
at the island of _Sal_, one of the Cape de Verds, and thence supply the
countries on the Niger, which was reported to be navigable for 500 miles
into the interior; and that they should bring back gold and slaves in
return; the latter to be brought to market at St Jago, another of the
Cape de Verd islands, where they would be immediately bought up for the
West Indies. All this fine speculation, however, rested on mistaken
foundations; as the Niger is altogether an inland river, running to the
east, and has no communication with the Senegal and Gambia, which run
west into the Atlantic. Yet time, and the civilization of the natives on
the Senegal and Gambia, may hereafter realize this scheme of a valuable
traffic into the interior of Africa;