Compass has a half-life of only about 12 years, so a compass that contains 120 mCi of tritium when new will contain only 60 when it is 12 years old, 30 when it is 24 years old, and so on. Consequently, the illumination of the display will fade. Mariners' compasses can have two or more magnets permanently attached to a compass card, which moves freely on a pivot. A "lubber line", which can be a marking on the compass bowl or a small fixed needle, indicates the ship's heading on the compass card. Traditionally the card is divided into thirty-two points
How Many Miles to Babylon? How Many Miles to Babylon? "How Many Miles to Babylon" is an English language nursery rhyme. It has a Roud Folk Song Index number of 8148. The accepted modern lyrics are: <poem>How many miles to Babylon? Three score miles and ten. Can I get there by candle-light? Yes, and back again.. If your heels are nimble and your toes are light, You may get there by candle-light.</poem> A longer Scottish version has the lyrics: <poem>King and Queen of Cantelon, How many miles to Babylon? Eight and eight, and other eight. Will I get there by candle-light? If your horse be