Celtic Rings
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Facts and Quotes:
During the 1600's the "knot" was used to determine a ships speed. To measure the speed and distance of a ship, knots were tied into a "log line." This line was thrown overboard, an hourglass was tipped, and the knots were counted. When the sand ran out, the counting stopped, and a general speed was determined. A "knot" was equal to one nautical mile per hour. So a ship sailing at 5 knots was traveling at 5 nautical miles per hour. What is a "nautical mile" you ask? A nautical mile is equal to about 1.15 survey miles, or 6080 feet. A nautical mile is the angular distance of one minute of arc on the Earth's surface. That means...if you break up the equator into 360 degrees, then break up those degrees into sixty minutes each, a nautical mile is the equivalent of one minute. But there are a few problems, the Earth isn't a perfect sphere, so the arc minute distances tend to vary from the pole to the equator.
