OOEANiO DISCOVERIES. 2T)1 



The iiiRaeiice exercised by Arabian civilization through the 

 astroiiomicai schools of Cordova, Seville, and Granada, on the 



tion of the journey" iu hours. A much more perfect way-measm*er 

 used both ou the water and on land, has been described by Hero of 

 Alexandria, the pupil of Ctesibius, in his still inedited Greek manuscript 

 on the Dioptra. (See Venturi, Comment supra la Storia dell' OUica, 

 Bologna, 1814, t. i., p. 134-i;^9.) There is notliing to be found ou the 

 subject we are considering iu the literature of the Middle Ages until 

 we come to the period of several " books of Nautical Instruction, " writ- 

 ten or printed in quick succession by Antonio Pigafetta ( Trattato di 

 Navigazione, probably before 1530); Francisco Falero (1535, a brother 

 of the astronomer Ruy Falero, who was to have accompanied Magellan 

 on his voyage round the world, and lefc behind him a " Regimiento 

 para observar la longitud en la mar") ; Pedro de Medina of Seville 

 {Arte de Navegar, 1545) ; Martin Cortes of Bnjalaroz {Breve Compendia 

 de la esfera, y de la arte de Navegar, 1551) ; and Andres Garcia de Ces- 

 pedes {^Regimiento de Navigacioii y Hidrograjia, 1G06). From almost 

 all these works, some of which have become extremely rare, as well as 

 Irom the Suma de Geograjia, which IMartin Fernandez de Enciso had 

 published in 1519, we learn, most distinctly, that the " distance sailed 

 over" is learned, in Spanish and Portuguese ships, uot by any distinct 

 measurement, but only by estimation by the eye, according to certain 

 established principles. Medina says (libro iii., cap. 11 and 12), "in 

 order to know the course of the ship, as to the length of distance passed 

 over, the pilot must set down in his register how much distance the 

 vessel has made according to hours {i. e., guided by the hour-glass, am- 

 polleta) ; and for this he must know that the most a ship advances iu 

 an hour is four miles, and with feebler breezes, three, or only two." 

 Cespedes {Regimiento, p. 99 and 156) calls this mode of proceeding 

 " echar punto por fantasia." This fantasia, as Enciso .justly remarks, 

 depends, if great errors are to be avoided, on the pilot's knowledge ot 

 the qualities of his ship : on the whole, however, every one who has> 

 been long at sea will have remarked, with surprise, when the waves 

 are not very high, how nearly the mere estimation of the ship's velocity 

 accords with the subsequent result obtained by the log. Some Spanish 

 pilots call the old, and, it must be admitted, hazardous method of mere 

 estimation (cueuta de estima) sarcastically, and certainly very incor- 

 rectly, "la corredera de los Holandeses, corredera de los perezosos," 

 In Columbus's ship's journal, reference is frequently made to the dis- 

 pute with Alonso Pinzon as to the distance passed over since their de- 

 parture from Palos. The hour or sand glasses, ampolletas. which they 

 made use of, ran out in half an hour, so that the interval of a day and 

 night was reckoned at 48 ampolletas. "We find in this important jour- 

 nal of Columbus (as, for example, on the 22d of Jaunary, 1493): "au' 

 daba 3 millas por hora hasta pasadas 5 ampolletas, y 3 antes que co- 

 menzase la guardia, que eran 8 ampolletas." (Navairete, t. i., p. 143.) 

 No mention is ever made of the log (la corredera). Are we to assume 

 that Columbus was acquainted with and employed it, and that he did 

 not think it necessary to name it, owing to its being already in very 

 general use, in the same way that Marco Polo has not mentioned tea, 

 or the great wall of China? Such an assumption appears to me very 

 improbable, because I find in the proposals made by the pilot, Don 

 Jayme Ferrer, 1495, for the exact determination of the position of the 

 papal line of demarkation, that when there is a question regarding the 



