Thus, during a long period of fifty-two years, this patriotic prince devoted almost his whole attention, and the ample revenues which he enjoyed as Duke of Viseo end grand master of the military order of Christ, in extending the maritime knowledge, and consequently the commercial prosperity of his country.  The incidents of the last seven years of the life of this distinguished prince, are involved in uncertainty, and we know very little with regard to the progress of his maritime discoveries from 1456, the date of the second of the voyages of Cada Mosto, of which we propose to give a separate account, till the year of his death, 1463.  From the year 1412, when he began his operations, at which time he could scarcely exceed fifteen years of age, the navigators who had been formed under his auspices and direction, and often instructed by himself in the theory of navigation and cosmography, gradually explored the western coast of Africa, from Cape Nam or Non, in lat. 28 deg. 15’, certainly to Rio Grande, in lat. 11 deg.  N. or rather to Rio de Nuno, not quite a degree farther south; but it is highly probable that the southern limit of discovery in his time extended to Cabo Verga, in lat. 10 deg.  N. the northern boundary of the country usually called the Sierra Liona, or the Ridge of Lions, perhaps to the gulf of Mitomba, or bay of Sierra Liona, in lat. 8 deg. 30’ N. an extent of 29 deg. 15’ of latitude, or 1185 nautical miles; a mere nothing certainly when compared with modern navigation, but a wonderful effort in the infancy of the science, when even coasting voyages of any extent along well known shores, and in frequented seas, were looked upon as considerable efforts.  No brilliant discovery, indeed, rewarded the perseverance of Don Henry, and the courage of his servants; but an indestructible foundation of useful knowledge was laid, for overthrowing the ignorant prejudices of the age, and by which, not long afterwards, his plans were perfected by completing the circumnavigation of Africa, and by the discovery of the New World.  Dr Vincent, the learned editor and commentator of the Periplus of the Erythrean Sea, is disposed to limit the discoveries of Don Henry to Cape Verd[2], but Ramusio believed that the Island of St Thomas was settled in his time; and the ingenious translator of the Lusiad of Camoens is of opinion that some of his commanders passed beyond the equator[3].  According to Mickle, it was the custom of his navigators to leave his motto, Talent de bien faire, wherever they came; and in 1525 Loaya, a Spanish captain, found that device carved on the bark of a tree in the island of St Matthew, or Anabon, in the second degree of southern latitude.  But this proof is quite inconclusive, as the navigators long reared in the school of this great prince might naturally enough continue his impress upon the countries they visited, even after his lamented death.