History Online - Columbus
[an error occurred while processing this directive]Discovery of America
The first voyage...
The Pinta, the Nina, and the Santa Maria were outfitted in the minor port of Palos. Columbus was aided in recruiting a crew by two brothers--Martin Alonzo Pinzon, who received command of the Pinta, and his younger brother Vicente Yanez Pinzon, who commanded the Nina. They left Palos on Aug. 3, 1492, rerigged the Nina in the Canaries, and sailed to the west. A landfall was made on the morning of Oct. 12, 1492, at an island in the Bahamas, which Columbus named San Salvador.
Not much of Columbus's own writing about the fourth voyage survives today. But we do know that while marooned on the north coast of Jamaica, he found his latitude to be 19°, which is within a degree of the correct number. This high accuracy could only have been achieved if Columbus had been using celestial techniques. It also suggests that even late in his life, Columbus continued to be fascinated with the latest navigational methods, and continued to learn.
The landing was met by Arawak, a friendly local population that Columbus called Indians. Some days later the expedition sailed on to Cuba, where delegations were landed to seek the court of the Mongol emperor of China and gold. In December they sailed east to Hispaniola, where, at Christmas, the Santa Maria was wrecked near Cap-Haitien. Columbus got his men ashore. The Indians seemed friendly; so 39 men were left on the island at the settlement of Navidad while Columbus returned to Spain on the Nina. He had sailed due west from the Canaries with favorable winds; now he sailed north before heading east and so again found favorable winds. Martin Alonzo Pinzon, who had explored on his own with the Pinta, rejoined Columbus, but the ships were separated at sea. Columbus finally landed (March 1493) in Lisbon and was interviewed by John II. Then he went to Palos and across Spain to Barcelona, where he was welcomed by Isabella and her husband, Ferdinand II of Aragon. Columbus claimed to have reached islands just off the coast of Asia and brought with him artifacts, Indians, and some gold.
Columbus and Celestial Navigation
The Third Voyage: Some Improvements?
In 1498, Columbus sailed from Spain with six ships of supplies for the settlers on Hispaniola. This is the only voyage on which Columbus made regular and serious attempts at celestial navigation. However, the results he obtained were quite poor, even by the standards of his day.
When he reached the Canary Islands, Columbus split his fleet: three ships would sail WSW, direct for Hispaniola, while Columbus himself would take the other three ships southward to the Cape Verde Islands, and then west. The reasons for this maneuver are still debated.
On the passage west from Cape Verde, he made a series of observations of the North Star to determine his latitude. According to Columbus, the North Star varied from 5° to 15° above the horizon, depending on the time of the night. Actually the North Star was about 3.5° from the celestial pole in 1498, so its total movement in altitude should have been seven degrees, not ten. (This 3.5 degree figure was known to navigators of that era trained in celestial techniques. This is evidence that Columbus was still unfamiliar with celestial navigation.)
The island of Trinidad lies close to the coast of Venezuela, and is separated from the mainland by two straits, which Columbus named Boca del Sierpe (serpent's mouth) and Boca del Drago (dragon's mouth). Columbus tried to measure the distance between these two straits using celestial observations. Here's a quote from a letter Columbus wrote to the King of Spain:
"I found that there between these two straits, which, as I have said, face each other in a line from north to south, it is twenty-six leagues from the one to the other, and I cannot be wrong in this because the calculation was made with a quadrant. . . . In that on the south, which I named la boca de la Sierpe, I found that at nightfall I had the pole star at nearly five degrees elevation, and in the other on the north, which I named la Boca del Drago, it was at almost seven."
The true altitudes of the North Star at these places (in 1498) would have been about 12.8° and 13.5° respectively; so Columbus's errors were about 8 and 6 degrees. This is very poor observation by any standard. Shortly after this, Columbus took ill and there were no further recorded attempts at celestial observation for the rest of the voyage.
The Fourth Voyage
At sea, Columbus measured distances in leagues, each of which was four miles long. But in the fifteenth century, there were many "mile" units of various lengths in use, both in Europe and in the Arabic world. This has given rise to disagreements over just how long (in modern terms) Columbus's league and mile were.
Samuel Eliot Morison assumed that Columbus used the "Roman" mile of 4860 feet. This would make his league 3.2 nautical miles long, which is the accepted length of the so-called Portuguese Maritime League (PML). The PML was known to be in common use among Spanish as well as Portuguese sailors.
The PML has serious problems, however. First, when we compare the distances Columbus reported sailing along the north coast of Cuba (between known points), we find these distances are much less than what Columbus reported. Also, if we accept Morison's landfall at Watlings Island, there are several other coastline lengths that would have been vastly overstated by Columbus. To solve these problems, Morison suggested that Columbus measured coastlines with a different length league (about 1.5 nautical miles) than he used for distances in the open sea. But there are no historical records that support such a league length; Morison's guess was entirely empirical.
Also, when tracing Columbus's transatlantic voyages (both eastbound and westbound), it is impossible to make the distances come out correctly when using the PML. Most of those who have traced the transatlatic tracks of Columbus have had to rely on fudge factors to make the distances come out correctly.
And finally, Columbus was Genoese, not Spanish. A shorter mile, the Italian or Geometric Mile of 4060 feet, was in common use in 15th century Italy. If Columbus used the Geometric Mile, his league would be 2.67 nautical miles, which is the accepted length of the Italian League, or Geometric League (GL). There are a number of 15th century documents on metrology that support this league length.
James E. Kelley, Jr. was the first to propose that Columbus used this league, in his 1983 paper (See bibliography). Kelley supported his thesis with an analysis showing how the shorter Geometric League, combined with an accounting of currents along the north coast of Cuba, could explain Columbus's overstated length of the island. In 1992, Douglas Peck showed that this league length could also reconstruct Columbus's transatlantic track without the usual fudge factors for distances.
For these reasons the 2.67 nautical mile Geometric League has gained wide support among historians as the league used by Columbus.
