OCEANIC DISCOVERIES. 671 



employed by Hipparchus could be applied, and the use of 

 lunar distances was recommended as early as 1514 by the 

 Nuremburg astronomer, Johann Werner, and soon afterwards 

 by Orontius Finaeus and Gemma Frisius. Unfortunately, 

 however, these methods also remained impracticable, until 

 after many fruitless attempts with the instruments of Peter 

 Apianus, (Bienewitz,) and Alonso de Santa Cruz, the mirror 

 sextant was invented by. the ingenuity of Newton, in 1 700, 

 and was brought in to use amongst seamen by Hadley in 1731. 

 The influence of the Arabian astronomers acted, through 

 the Spaniards, on the general progress of nautical astronomy. 

 Many methods were certainly attempted for determining the 



^ longitude which did not succeed ; and the fault of the want of 

 success was less rarely ascribed to the incorrectness of the 

 observation, than to errors of printing in the astronomical ephe- 

 merides of Regiomontanus which were then in use. The Por- 

 tuguese even suspected the correctness of the astronomical data 

 as given by the Spaniards, whose tables they accused of being 

 falsified from political grounds.*' The suddenly awakened desire 

 for the auxiliaries which nautical astronomy promised, at any 

 rate theoretically, is most vividly expressed in the narrations 

 of the travels of Columbus, Amerigo Vespucci, Pigafetta, and 

 of Andreas de San Martin, the celebrated pilot of the 

 Magellanic expedition, who was in possession of the methods 



......of Ruy Falero for determining the longitude. Oppositions of 



planets, occultations of the stars, differences of altitude 

 between the moon and Jupiter, and changes in the moon's 

 declination, were all tried with more or less success. We 

 possess observations of conjunction by Columbus, on the night 

 of the 13th of January, 1493, at Hayti. The necessity for 

 attaching a special and well-informed astronomer to every 

 great expedition was so generally felt, that Queen. Isabella 

 wrote to Columbus on the 5th of September, 1493, " that 

 although he had shown in his undertakings that he knew more 

 than any other living being (que ninguno de los nacidos), she 

 counselled him, nevertheless, to take with him Fray Antonio j 

 de Marchena, as being a learned and skilful astronomer." 

 Columbus writes in the narrative of his fourth voyage, that 

 " there was only one infallible method of taking a ship's 

 reckoning, viz., that employed by astronomers. He who 

 understands it, may rest satisfied; for that which it yields is 

 * Barros, Dec. iii. parte 2. pp. 050 and 658-662. 



