HORIZON and into two equal parts, by the verticals.—The sensible horizon is divided into eastern and western. The eastern or oriental horizon, is that part of the horizon wherein the heavenly bodies rise. The western or occidental horizon, is that wherein the stars set. The altitude or elevation of any point of the sphere, is an arch of a vertical circle intercepted between it and the sensible horizon.
By sensible horizon is also frequently meant a circle, which determines the segment of the surface of the earth, over which the eye can reach; called also the physical horizon. In this sense we say, a spacious horizon, a narrow scanty horizon.