For many years, on large ocean-going ships, there has been a certain very important room. Usually it is called the chart room. Here are kept the maps, the drawings, the charts, which contain all that is known of the great waters of the world - shore lines, ocean depths, islands, reefs, rocks. Here the ship's officers check to see where they are, what their position is, how best to steer in order to reach their distant port.

When you come to chu…