When Humboldt wrote the _Examen Critique_, Toscanelli’s letter to Columbus, of unknown date,[493] enclosing a copy of the one he sent to Martinez in 1474, was known only in the Italian form in Ulloa’s translation of the _Historie del S. D. Fernando Colombo_ (Venice, 1571), and in the Spanish translation of Ulloa’s version by Barcia in the _Historiades primitivos de las Indias occidentales_ (Madrid, 1749), i. 5 bis, which was reprinted by Navarrete, _Coleccion de los viages y descubrimientos_, etc., ii. p. 1. In the letter to Martinez, in this form, it is said that there are in the map which accompanied it twenty-six _spaces_ between Lisbon and _Quisai_, each space containing 250 miles according to the Ulloa version, but according to the re-translation of Barcia 150 miles. This, with several other changes made by Barcia, were followed by Navarrete and accepted as correct by Humboldt, who severely censures Ximenes for adopting the Italian rendering in his _Gnomone fiorent_. But the Latin copy of the letter in Columbus’s handwriting, discovered by Harrisse and made public (with fac-simile) in his _D. Fernando Colon_ (Seville, 1871),[494] sustained the correctness of Ulloa’s version, giving 250 miliaria to the space. This authoritative rendering also showed that while the translator had in general followed the text, he had twice inserted a translation of miles into degrees, and once certainly, incorrectly, making in one place 100 miles = 35 leagues, and in another, 2,500 miles = 225 leagues. Probably this discrepancy led to the omissions made by Barcia; he was wrong, however, in changing the number 250, supposing the 150 not to be a typographical error, and in omitting the phrase, “which space (from Lisbon to Quinsai) is about the third part of the sphere.” The Latin text showed, too, that this whole passage about distances was not in the Martinez letter at all, but formed the end of the letter to Columbus, since in the Latin it follows the date of the Martinez letter, into which it has been interpolated by a later hand. Finally the publication of Las Casas’s _Historia de las Indias_ (Madrid, 1875) gave us another Spanish version, which differs from Barcia’s in closely agreeing with the Ulloa version, and which gives the length of a space at 250 miles. There were then 26 × 250 = 6500 miles between Lisbon and Quinsai, and this was about one third of the circumference of the earth in this latitude, but it is not clear whether Roman or Italian miles were meant.