Posted on Leave a comment

Measuring the length of the meridian

Meridian stamp 1736-1986
Meridian stamp 1736-1986
Meridian stamp 1736-1986

Measuring the length of the meridian led to the invention of the meter.   Theoretically a degree of latitude is a constant, the same at the equator as at the pole. However, Isaac Newton believed that the earth was slightly flattened at the poles, an oblate spheroid, and that the length of a degree at the poles was longer than it was at the equator. On the other hand French mathematicians argued either for a perfect sphere or for a prolate spheroid, one which bulged at the poles. 

Continue reading Measuring the length of the meridian

Advertisements
Posted on Leave a comment

Columbus Fleet 1893 Issue

Columbus Fleet 1893 Issue

English: US Postage stamps:

Columbian issues of 1893, 3c and 4cDate 1893

Source US Post Office

400th Anniversary Issues of 1893

U.S. stamps reflecting the most commonly held view as to what Columbus’ first fleet might have looked like. The Santa Maria, the flagship of Columbus’ fleet, was a carrack—a merchant ship of between 400 and 600 tons, 75 feet (23 m) long, with a beam of 25 feet (7.6 m), allowing it to carry more people and cargo. It had a deep draft of 6 feet (1.8 m). The vessel had three masts: a mainmast, a foremast, and a mizzenmast. Five sails altogether were attached to these masts. Each mast carried one large sail. The foresail and mainsail were square; the sail on the mizzen was a triangular sail known as a lateen mizzen. The ship had a smaller topsail on the mainmast above the mainsail and on the foremast above the foresail. In addition, the ship carried a small square sail, a spritsail, on the bowsprit.