Changes

'''Lines of longitude''' or '''meridians''' are imaginary lines that run north and south across the earth.  They are used to measure east-west location, relative to a "prime meridian" which by definition is 0&deg;.  While in the past many meridians have been used, since 1884 the Greenwich Meridian has become the universal standard.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>

'''Lines of longitude''' or '''meridians''' are imaginary lines that run north and south across the earth.  They are used to measure east-west location, relative to a "prime meridian" which by definition is 0&deg;.  While in the past many meridians have been used, since 1884 the Greenwich Meridian has become the universal standard.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> Longitude is an ''angular'' measurement and is given in degrees, minutes, and seconds, represented by the symbols &deg;, ', and " respectively.

Although lines of longitude may be imaginary, they are very important to navigators; [[Lewis Carroll]] joked about this in his long nonsense poem [[The Hunting of the Snark]]:

Although lines of longitude may be imaginary, they are very important to navigators; [[Lewis Carroll]] joked about this in his long nonsense poem [[The Hunting of the Snark]]: