Base Line. A horizontal line forming the base of a medallic design, often separating the device from the exergue. The base line is important in determining the horizontal orientation of the design; features like horizon, water line, base of buildings are parallel to this, as is inscription lettering. Flag poles, sides of buildings and other vertical lines are, of course, perpendicular to the base line in a linear perspective of the design. Compare listel, register, ground line.

Also an imaginary base line is also the plane for all lettering on a medallic design;

these appear mostly in a straight line for all inscriptional wording, or in an arc (bowed lettering) for those in the legend. Infrequently an undulating base line will be used for lettering appearing in a wave for artistic effect. An example of several kinds of base lines (undulating, bowed, and straight) appear on the reverse of the City College of New York Medal of 1866 (Julian CM-14), and on the reverse of the Cyrus West Field Congressional Medallion, 1868 (Julian PE-10), both struck by the United States Mint.

Lettering without use of a base line, or staggered base line exist but are rare. An

example is the letting on the obverse of the W.H. Nicholas Medal (issued by the New York Chapter of the American Chemical Society). It was designed by Henry M. Toch who placed the letters in the chemical fumes emanating from heating a retort (from H.B. Wechsler's painting, Alchemist).

Reference:

O37 {1977} Julian.