Page 147

I'm I hope thus far to have made it plain just how a locality may be fine fixed, even though it be in mid-ocean. But that is only a small part of the problem. Of what use to the sailor to know that he was in some definite lat. and long, if he didn’t know what lat. and long. He was? He approach now the task of explaining how he can, with assurance, but the point of his pencil on exactly the spot on his chart that represents the position of his ship, at the moment.

It should be said at the beginning the chart is, and essential to all navigation, a government chart is a remarkable piece of work, in many respects undoubtedly the most scientifically and, carefully prepared drawing ever put on paper. It shows in picture language exactly the thing that a sailor wishes to know, so far as they can be told at all. It shows the configuration of the coast, the position of all dangers, the depth of all waters, the character of the bottom of the location of the lights and buoys and, especially, exact distances and directions by compass. If the sailor knows where he is on the chart, it is easy to see in just what direction he must steer to arrive at his destination, and just what dangers he must avoid on the way.

A small section of the chart is shown on page 146, representing the coastwise waters from Sandy Hook to the Delaware Capes. Two very important details of this chart or not shown in the drawing for lack of room. One of these is the scale, by which, distance can be accurately measured: the other is the compass diagram, which on an entire chart shows the compass directions – the "bearings”  as the sailor calls them. The compass is, of course, the most important item of the navigators outfit. It is to be supposed that every one knows what a compass is; that it is, in simplest form, a magnetized steel needle, delicately pivoted at its centre, the ends of which, if it is free to…

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