OCEANIC DISCOVERIES. 633 



Cairo were imitated, on a small scale, for nautical purposes. 

 Their names even were transferred; thus, for instance, that 

 of " astrolabon," given by Martin Behaim to the mainmast, 

 belongs originally to Hipparchus. When Yasco de Gama 



pedes (Regimiento, pp. 99 and 156) calls this mode of proceeding " echar 

 ptmto por fantasia." This fantasia, as Enciso justly remarks, depends, if 

 great errors are to be avoided, on the pilot's knowledge of 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 

 (cuenta de estima), sarcastically, and certainly very incorrectly, " la 

 corredera de los Holandeses, corredera de los perezosos." In Colum- 

 bus' ship's journal, reference is frequently made to the dispute with 

 Alonso Pinzon, as to the distance passed over since their departure 

 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 journal of Colum- 

 bus (as, for example, on the 22nd of January, 1493) : " andaba 8 millas 

 por hora hasta pasadas 5 ampolletas, y 3 antes que comenzase la guardia, 

 que eran 8 ampolletas." (Navarrete, 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 demarcation, that 

 when there is a question regarding the distance sailed over, the appeal 

 is made only to the accordant judgment (juicio) of twenty very experi- 

 enced seamen (" que apunten en su carta de 6 en6 horas el camino que. 

 la nao fara segun su juicio"). If the log had been in use, no doubt 

 Ferrer would have indicated how often it should be thrown. I find the 

 first mention of the application of the log in a passage of Piga- 

 fetta's Journal of Magellan's voyage of circumnavigation, which long lay 

 buried among the manuscripts in the Ambrosian Library at Milan. It 

 is there said, that, in the month of January 1521, when Magellan had 

 already arrived in the Pacific, " Secondo la misura che facevamo del 

 viaggio colla catena a poppa, noi percorrevamo da 60 in 70 leghe al 

 giorno" (Amorelli, Primo Viaggio intorno al Olobo terracqueo, ossia 

 Navigazionefatta dal Cavalier e Antonio Pigafetta sulla squadra del 

 Cap. Magaglianes, 1800, p. 46). What can this arrangement of a chain 

 at the hinder part of the ship (catena a poppa), " which we used through- 

 out the entire voyage to measure the way," have been, except an apparatus 

 similar to our log] No special mention is made of the log-line divided 

 into knots, the ship's log, and the half-minute or log-glass, but this 



