Born at Alcacer do Sal, the celebrated scientist PEDRO NUNEZ (1492?-1577?), whose name lives in the instrument of his invention, the _nonius_,[528] was Cosmographer to Kings João III and Sebastian and Professor of Mathematics at the University of Coimbra (1544-62). Prince Luis and D. João de Castro were his pupils. He wrote indifferently in Latin, Spanish, or Portuguese, declared that as science treats of concrete things it can be expressed in any language however barbarous,[529] and, in order to secure for it a wider public, translated into Portuguese the Latin treatise (_libellus_) _De Sphaera_ by John of Halifax (Joannes de Sacro Bosco): _Tratado da Sphera_ (1537),[530] and into Spanish his own _Libro de Algebra en arithmetica & geometria_ (1567), originally written in Portuguese and addressed to his pupil and friend the Cardinal-King Henrique. His other works, including the _De Crepusculis_ (1542), were written in Latin. The Homeric hero DUARTE PACHECO PEREIRA (1465?-1533?), about whose life, apart from the hundred days at Cochin (1504) and a fight off Finisterre (1509) with the French pirate Mondragon, singularly little is known,[531] on his return from India in 1505 wrote a work entitled _Esmeraldo de Situ Orbis_ [1505-6?]. This curious and important survey of the coast of Africa, the work of one more accustomed to wield sword than pen, but sometimes as picturesque and interesting as Duarte Barbosa, was to have consisted of five books, but only three and a part of the fourth were written. It remained in manuscript for nearly four centuries. The three _Roteiros_ (logs)[532] written by the famous Viceroy D. JOÃO DE CASTRO (1500-48) on his voyages (1) from Lisbon to Goa in 1538, (2) from Goa to Diu, 1538-9, (3) from Goa to the Red Sea in 1541, are decked out with no literary graces. He wrote, he said, for seamen, not for ladies and gallants. Yet the scientific curiosity and enthusiasm of this keen-eyed, broad-minded observer give his descriptions force and truth, the same practical lucidity that marks his letters, which according to his friend Prince Luis contained _todas as cousas necessarias e nenhũas superfluas_, and they were early prized in Spain as _harto notables, muy curiosos_.[533] The third _Roteiro_ would seem to have been originally written in Latin, and perhaps translated by Castro at his beloved Sintra home. The manuscript was bought by Sir Walter Raleigh, and it appeared in English in 1625, 208 years before it was published in Portuguese.