Nautical Terminator – Tradewinds (Part 1)

By Edmond Halley – http://libweb5.princeton.edu/visual_materials/maps/websites/thematic-maps/quantitative/meteorology/meteorology.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=69162530

          Everyone knows that the trade winds, from which our club takes its name, are the reliable easterlies that were followed when most freight was carried under sail. But is this mercantile association the real reason they are called “trade winds?”

          The contemporary uses of the word “trade,” as in commerce, and “trade,” as it applies to the winds, have a common ancestor, but not the same meaning. Both come from the Old English “tredan,” which means course or path, as in “path of life.” The word is related to “tread,” and refers to the habitual way one carries out one’s day. Some of us are impulsive and changeable, but most folks spend their lives in a regular activity practiced without much variation—their “trade.” By the same token, some winds are fickle, but others have a regular, dependable course. It was this consistency that originally earned these winds their name, not their commercial value.

          The trade winds are among the most ancient meteorological phenomena on the planet, but they were still unknown in Europe by the time of Columbus’ first voyage. According to Samuel Eliot Morison, the dean of Columbus scholars, the great discoverer set his course not according to these as yet unproven winds, but directly—or so he thought—towards Japan, due west from the Canaries. In a normal year his departure from La Gomera, at 28 degrees, would have been several hundred miles north of the trade winds. Sailing west should have becalmed him in the horse latitudes, and he may never have made his fabled discoveries. However, in addition to daring and perseverance, Columbus profited from excellent luck. He made his passage on a year when the Atlantic trades were much higher in latitude than is common, and he reports enjoying a perfect following breeze. But why would he have thought to sail further south? No one had ever gone before him, and it would be over 300 years until the Atlantic and Pacific trade winds were systematically recorded by Mathew Maury.

          On his second voyage, for reasons again unrelated to the wind, Columbus headed West by South from the Canaries, finding steady breezes at a lower latitude. Before long, navigators came to expect them and soon they were calling them the “trade,” meaning constant, winds. Next time, we will discuss why they are so constant—so constant, in fact, that they have been blowing forever.

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