MERIDIAN LINE

A line traced on the surface of the earth, coinciding with the intersection of the meridian of the place with the sensible horizon. MERIDIAN OF A GLOBE, OR THE BRASS MERIDIAN, is a graduated circular ring, within which the globe is suspended and revolves, and by means of which it is connected with the frame bearing the horizontal scale. Meridian lines are also traced on the globe itself, usually at 15° distance, or a difference of longitude corresponding to an hour of time. It is probable that these, with the parallels of latitude, suggested to Des cartes the idea of co-ordinates, which he applied so succe fully to connect algebra with geometry. [s. 746]