THE
NATIONAL GEOGRAPHIC MAGAZINE.
Vol. II. 1890. No. 1.
ON THE TELEGRAPHIC DETERMINATIONS OF LONGITUDE BY THE BUREAU OF NAVIGATION.
BY LIEUT. J. A. NORRIS, U. S. N.
The following definitions are given by Chauvenet in his Spherical and Practical Astronomy.
"The longitude of a point on the earth's surface is the angle at the Pole included between the meridian of that point and some assumed first meridian. The difference of longitude between any two points is the angle included between their meridians." To describe the practical methods of obtaining this difference or angle, by means of the electric telegraph both overland and submarine, and especially those employed by the expeditions sent out by the Navy department, is the object of this paper.