With these impediments to accurate results, it is not surprising that even errors of considerable extent crept into the records of latitude, and long remained unchallenged.[381] Ptolemy, in A. D. 150, had placed Constantinople two degrees out of the way; and it remained so on maps for fourteen hundred years. In Columbus’ time Cuba was put seven or eight degrees too far north; and under this false impression the cartography of the Antilles began.
The historic instrument for the taking of latitude was the astrolabe, which is known to have been in use by the Majorcan and Catalanian sailors in the latter part of the thirteenth century; and it is described by Raymond Lullius in his Arte de navegar of that time.[382] Behaim, the contemporary of Columbus, one of the explorers of the African coast, and a pupil of Regiomontanus, had somewhat changed the old form of the astrolabe in adapting it for use on shipboard. This was in 1484 at Lisbon, and Behaim’s improvement was doubtless what Columbus used. Of the form in use before Behaim we have that (said to have belonged to Regiomontanus) in the cut on page 96; and in the following cut the remodelled shape which it took after Behaim.
LATER ASTROLABE.
This cut follows an engraving (Mag. of Amer. Hist., iii. 178) after a photograph of one used by Champlain, which bears the Paris maker’s date of 1603. There is another cut of it in Weise’s Discoveries of America, p. 68. Having been lost by Champlain in Canada in 1613, it was ploughed up in 1867 (see Vol. IV. p. 124; also Canadian Monthly, xviii. 589). The small size of the circle used in the sea-instrument to make it conveniently serviceable, necessarily operated to make the ninety degrees of its quarter circle too small for accuracy in fractions. On land much larger circles were sometimes used; one was erected in London in 1594 of six feet radius. The early books on navigation and voyages frequently gave engravings of the astrolabe; as, for instance, in Pigafetta’s voyage (Magellan), and in the Lichte der Zee-Vaert (Amsterdam, 1623), translated as The Light of Navigation (Amsterdam, 1625). The treatise on navigation which became the most popular with the successors of Columbus was the work of Pedro de Medina (born about 1493), called the Arte de navegar, published in 1545 (reprinted in 1552 and 1561), of which there were versions in French (1554, and Lyons, 1569, with maps showing names on the coast of America for the first time), Italian (1555 with 1554, at end; Court Catalogue, no. 235), German (1576), and English (1591). (Harrisse, Bibl. Amer. Vet., no. 266.) Its principal rival was that of Martin Cortes, Breve compendio de la sphera y de la arte de navegar, published in 1551. In Columbus’ time there was no book of the sort, unless that of Raymond Lullius (1294) be considered such; and not till Enciso’s Suma de geografia was printed, in 1519, had the new spirit instigated the making of these helpful and explanatory books. The Suma de geografia is usually considered the first book printed in Spanish relating to America. Enciso, who had been practising law in Santo Domingo, was with Ojeda’s expedition to the mainland in 1509, and seems to have derived much from his varied experience; and he first noticed at a later day the different levels of the tides on the two sides of the isthmus. The book is rare; Rich in 1832 (no. 4) held it at £10 10s. (Cf. Harrisse, Notes on Columbus, 171; Bibl. Amer. Vet., nos. 97, 153, 272,—there were later editions in 1530 and 1546,—Sabin, vol. vi. no. 22,551, etc.; H. H. Bancroft, Central America, i. 329, 339; Carter-Brown, vol. i. no. 58, with a fac-simile of the title: Cat. Hist. do Brazil, Bibl. Nac. do Rio de Janeiro, no. 2.) Antonio Pigafetta in 1530 produced his Trattato di navigazione; but Medina and Cortes were the true beginners of the literature of seamanship. (Cf. Brevoort’s Verrazano, p. 116, and the list of such publications given in the Davis Voyages, p. 342, published by the Hakluyt Society, and the English list noted in Vol. III. p. 206, of the present History.) There is an examination of the state of navigation in Columbus’ time in Margry’s Navigations Françaises, p. 402, and in M. F. Navarrete’s Sobre la historia de la náutica y de las ciencias matemáticas, Madrid, 1846,—a work now become rare.
The rudder, in place of two paddles, one on each quarter, had come into use before this time; but the reefing of sails seems not yet to have been practised. (Cf. De Gama’s Voyages, published by the Hakluyt Society, p. 242.) Columbus’ record of the speed of his ship seems to have been the result of observation by the unaided eye. The log was not yet known; the Romans had fixed a wheel to the sides of their galleys, each revolution of which threw a pebble into a tally-pot. The earliest description which we have in the new era of any device of the kind is in connection with Magellan’s voyage; for Pigafetta in his Journal (January, 1521), mentions the use of a chain at the hinder part of the ship to measure its speed. (Humboldt, Cosmos, Eng. tr., ii. 631; v. 56.) The log as we understand it is described in 1573 in Bourne’s Regiment of the Sea, nothing indicating the use of it being found in the earlier manuals of Medina, Cortes, and Gemma Frisius. Humfrey Cole is said to have invented it. Three years later than this earliest mention, Eden, in 1576, in his translation of Taisnier’s Navigatione, alludes to an artifice “not yet divulgate, which, placed in the pompe of a shyp, whyther the water hath recourse, and moved by the motion of the shypp, with wheels and weyghts, doth exactly shewe what space the shyp hath gone” (Carter-Brown Catalogue, i. no. 310),—a reminiscence of the Roman side-wheels, and a reminder of the modern patent-log. Cf. article on “Navigation” in Encyclopedia Britannica, ninth ed. vol. xvii.
An instrument which could more readily adapt itself to the swaying of the observer’s body in a sea-way, soon displaced in good measure the astrolabe on shipboard. This was the cross-staff, or jackstaff, which in several modified forms for a long time served mariners as a convenient help in ascertaining the altitude of the celestial bodies. Precisely when it was first introduced is not certain; but the earliest description of it which has been found is that of Werner in 1514. Davis, the Arctic navigator, made an improvement on it; and his invention was called a backstaff.
While the observations of the early navigators in respect to latitude were usually accompanied by errors, which were of no considerable extent, their determinations of longitude, when attempted at all, were almost always wide of the truth,[383]—so far, indeed, that their observations helped them but little then to steer their courses, and are of small assistance now to us in following their tracks. It happened that while Columbus was at Hispaniola on his second voyage, in September, 1494, there was an eclipse of the moon.[384] Columbus observed it; and his calculations placed himself five hours and a half from Seville,—an error of eighteen degrees, or an hour and a quarter too much. The error was due doubtless as much to the rudeness of his instruments as to the errors of the lunar tables then in use.[385]
