The standard unit in the measure of electrical resistance,
   being the resistance of a circuit in which a potential difference of
   one volt produces a current of one ampere. As defined by the
   International Electrical Congress in 1893, and by United States
   Statute, it is a resistance substantially equal to 109 units of
   resistance of the C.G.S. system of electro-magnetic units, and is
   represented by the resistance offered to an unvarying electric current
   by a column of mercury at the temperature of melting ice 14.4521 grams
   in mass, of a constant cross-sectional area, and of the length of 106.3
   centimeters. As thus defined it is called the international ohm.