C. Fitzpatrick, _Phil. Trans._, 1888, p. 179, or _Proc. Roy.
Soc._, 1888, p. 44, or _Electrician_, 1888, 21, p. 538; "Recent
Determinations of the Absolute Resistance of Mercury," R. T.
Glazebrook, _Electrician_, 1890, 25, pp. 543 and 588. Also see J. V.
Jones, "On the Determination of the Specific Resistance of Mercury in
Absolute Measure," _Phil. Trans._, 1891, A, p. 2. Table IV. gives the
values of the volume-resistivity of mercury as determined by various
observers, the constant being expressed (a) in terms of the resistance
in ohms of a column of mercury one millimetre in cross-section and 100
centimetres in length, taken at 0 deg. C.; and (b) in terms of the
length in centimetres of a column of mercury one square millimetre in
cross-section taken at 0 deg. C. The result of all the most careful
determinations has been to show that the resistivity of pure mercury
at 0 deg. C. is about 94,070 C.G.S. electromagnetic units of
resistance, and that a column of mercury 106.3 centimetres in length
having a cross-sectional area of one square millimetre would have a
resistance at 0 deg. C. of one international ohm. These values have
accordingly been accepted as the official and recognized values for
the specific resistance of mercury, and the definition of the ohm. The
table also states the methods which have been adopted by the different
observers for obtaining the absolute value of the resistance of a
known column of mercury, or of a resistance coil afterwards compared
with a known column of mercury. A column of figures is added showing
the value in fractions of an international ohm of the British
Association Unit (B.A.U.), formerly supposed to represent the true
ohm. The real value of the B.A.U. is now taken as .9866 of an
international ohm.

TABLE IV.--_Determinations of the Absolute Value of the
Volume-Resistivity of Mercury and the Mercury Equivalent of the
Ohm._

+-----------------+------+----------------------+--------+----------+---------+
| | | | |Value of |Value of |
| | | |Value of|100 Centi-|Ohm in |
| Observer. | Date.| Method. |B.A.U. |metres of |Centi- |
| | | |in Ohms.|Mercury |metres of|
| | | | |in Ohms. |Mercury