You may suppose the following figure to
be a globe or sphere, representing the earth. The outermost
circle, marked with the letters A, D, B, C, is called the meridian; and
on this circle the latitude is reckoned, either from C towards A or B,
or else from D towards A and B.
The equator is the line C, D, which upon the globe is a circle, and is
sometimes called the equinoctial: Upon this circle the degrees of
longitude are reckoned, beginning at C, and counting all round the
globe till you come to C again; and O is the middle of the world
between A and B, which are the two poles thereof: A representing the
North Pole, B the South Pole.
The circles E F, and G H, are called the Tropics, beyond which the sun