Work on the Arctic pole.
In his letter to Doña Juana, Columbus says that he has deposited a work in the Convent de la Mejorada, in which he has predicted the discovery of the Arctic pole. It has not been found.
Missing letters.
Harrisse also tells us of the unsuccessful search which he has made for an alleged letter of Columbus, said in Gunther and Schultz's handbook of autographs (Leipzig, 1856) to have been bought in England by the Duke of Buckingham; and it was learned from Tross, the Paris bookseller, that about 1850 some autograph letters of Columbus, seen by him, were sent to England for sale.
Columbus's maps.
After his return from his first voyage, Columbus prepared a map and an accompanying table of longitudes and latitudes for the new discoveries. They are known to have been the subject of correspondence between him and the queen.
There are various other references to maps which Columbus had constructed, to embody his views or show his discoveries. Not one, certainly to be attributed to him, is known, though Ojeda, Niño, and others are recorded as having used, in their explorations, maps made by Columbus. Peter Martyr's language does not indicate that Columbus ever completed any chart, though he had, with the help of his brother Bartholomew, begun one. The map in the Ptolemy of 1513 is said by Santarem to have been drawn by Columbus, or to have been based on his memoranda, but the explanation on the map seems rather to imply that information derived from an admiral in the service of Portugal was used in correcting it, and since Harrisse has brought to light what is usually called the Cantino map, there is strong ground for supposing that the two had one prototype.
Italian notarial records.