Fig. 95.—Protractor Set by Dipping Needle
Showing Latitude.
How to Find Latitude.—The latitude of a place on the Earth’s surface is its distance north or south of the equator. This distance is usually measured in degrees of a circle, instead of in miles.
The equator is called 0 (zero) degrees, and the north and south poles are 90 degrees from the equator, as shown in [Fig. 93]. If you are in Philadelphia, Pennsylvania, or Quincy, Illinois, or Tehama, California, you are in latitude 40 degrees. If you are in Bangor, Maine, St. Paul, Minnesota, or Portland, Oregon, you are in latitude 45 degrees, or just halfway between the north pole and the equator, as [Fig. 94] shows.
(1) An easy way to find roughly the latitude of a place, that is, its distance from the equator, is to use a dipping needle and a protractor.
To make a protractor cut out a semi-circle of stiff, white cardboard, just the size shown in [Fig. 93], and mark the figures on the edge and draw lines from the edge to the center point exactly as in the picture.
Fig. 96.—Two Sticks Screwed
Together.
Fig. 97.—Two Sticks Across
Bucket of Water.
Now place your dipping needle on a level board or table and set the center of your cardboard protractor in line and on a level with the axis of the needle, as shown in [Fig. 95]. Whatever line on the protractor the dip of the needle takes the degree marked on the edge of the protractor will be the magnetic latitude you are in.