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.