perspective, is a plane parallel to the horizon, passing through the eye, and cutting the perspective plane at right angles.

HORIZONTAL Projection. See Geography, no 66, 69.

HORIZONTAL Range, or Level Range, of a piece of ordnance, is the line it describes, when directed parallel to the horizon or horizontal line. See Gunnery, paffim.

HORIZONTAL Moon. See Astronomy, no 374.

HORIZONTAL Speculum. See Speculum.