Ecliptic—That plane passing through the center of the sun in which lies the orbit of the earth. Also used to designate the apparent path of the sun in the heavens.
Elgin—A city in Illinois, U. S. A., in which is located the Elgin National Watch Company—one of the largest factories in the United States.
End-Shake—Freedom of pivots to move endways. Necessary in a watch or clock because there is no force to spare and a tight pivot would stop the movement.
End-Stone—A small disc of jewel against which the end of a pivot sets. See [Capped Jewel].
End-Stop—In a watch the same as end-stone.
Engaging Friction—Friction which results when the teeth of two wheels gearing together come into action before reaching the line of centers—that is, a line drawn from center to center of the gearing wheels.
Engine-Turning—A pattern of curved lines cut into metal for decoration. Introduced about 1770 by Francis Guerint of Geneva. The earliest specimens were cut very deep but shallower cutting soon became the rule.
Engraving—A form of ornamenting metals in which the design is cut into the metal. In "Champ-leve" engraving the ground is cut away leaving the design in relief.
Epact—The excess in time of the solar year over the period of 12 lunar months, amounting to about 11 days. The new moons will thus fall about 11 days earlier in each succeeding year. In a calendar so arranged 30 days are taken off every fourth year, as an intercalary month, the moon having revolved once in that time, and the three days remaining would be the epact. The epact thus continues to vary until at the end of nineteen years the new moons return as at first.