Term Knot

The term knot, or nautical mile, is used world-wide to denote one's speed through water. Today, we measure knots with electronic devices, but 200 years ago such devices were unknown. 

Ingenious marines devised a speed measuring device both easy to use and reliable, the "log line." From this method we get the term "Knot." The log line was a length of twine marked at 47.33-foot intervals by colored knots. At one end a log chip was fastened. It was shaped like the sector of a circle and weighted at the rounded end with lead. When thrown over the stern, it would float pointing upward and would remain relatively stationary. The log line was allowed to run free over the side for 28 seconds and then hauled on board. Knots which had passed over the side were counted. In this way, the ships speed was measured.

North Magnetic Pole

 The Earth's magnetic field is shaped approximately like that of a bar magnet and, like a magnet, it has two magnetic poles, one in the Canadian arctic, referred to as the North Magnetic Pole, and one off the coast of Antarctica, south of Australia, referred to as the South Magnetic Pole. At the North Magnetic Pole the Earth's magnetic field is directed vertically downward relative to the Earth's surface. Consequently, magnetic dip, or inclination is 90°. In addition, the North Magnetic Pole is the eventual destination for a traveller who follows his or her compass needle from anywhere on Earth.

The North Magnetic Pole is slowly drifting across the Canadian Arctic. The 

Geological Survey of Canada keeps track of this motion by periodically carrying out magnetic surveys to redetermine the Pole's location. The survey indicates position for the Pole and established that it is moving approximately northwest at 40 km per year.

The observed position for 2001 and estimated positions for 2002 to 2005 are given in the table.

Year	Latitude ( °N)	Longitude ( °W)
2001	81.3	110.8
2002	81.6	111.6
2003	82.0	112.4
2004	82.3	113.4
2005	82.7	114.4