INTERNATIONAL DATE LINE. If a voyager travel eastward to the Antipodes and thus "anticipate the sun," his timing will be 12 hours in advance; if another travel westward, then his will be as much in arrear. There will thus be a differ ence of 24 hours when they meet. To avoid confusion, mariners chose the 180° meridian as a convenient line (known as the International Date Line), at the crossing of which they changed the name of the day, forward if going west ; backwards if going east. The International Date Line, largely consequent on Ameri can initiative, while retaining the 180° meridian in the Pacific, is arranged so as to bring the Aleutian islands and Alaska into the same dating as America, and certain of the South Sea islands into the same dating as Australia and New Zealand.