nstruction of a standard wire-resistance
coil on the plan adopted by the Berlin Physikalisch-Technische
Reichsanstalt is given in the Report of the British Association
Committee on Electrical Standards, presented at the Edinburgh Meeting
in 1892. For the design and construction of standards of electric
resistances adapted for employment in the comparison and measurement
of very low or very high resistances, the reader may be referred to
standard treatises on electric measurements.

BIBLIOGRAPHY.--See also J. A. Fleming, _A Handbook for the Electrical
Laboratory and Testing Room_, vol. i. (London, 1901); _Reports of the
British Association Committee on Electrical Standards_, edited by
Fleeming Jenkin (London, 1873); A. Matthiessen and C. Vogt, "On the
Influence of Temperature on the Conducting Power of Alloys," _Phil.
Trans._, 1864, 154, p. 167, and _Phil. Mag._, 1865, 29, p. 363; A.
Matthiessen and M. Holtzmann, "On the Effect of the Presence of Metals
and Metalloids upon the Electric Conducting Power of Pure Copper,"
_Phil. Trans._, 1860, 150, p. 85; T. C. Fitzpatrick, "On the Specific
Resistance of Copper," _Brit. Assoc. Report_, 1890, p. 120, or
_Electrician_, 1890, 25, p. 608; R. Appleyard, _The Conductometer and
Electrical Conductivity_; Clark, Forde and Taylor, _Temperature
Coefficients of Copper_ (London, 1901). (J. A. F.)

II. CONDUCTION IN LIQUIDS

Through liquid metals, such as mercury at ordinary temperatures and
other metals at temperatures above their melting points, the electric
current flows as in solid metals without changing the state of the
conductor, except in so far as heat is developed by the electric
resistance. But another class of liquid conductors exists, and in them
the phenomena are quite different. The conductivity of fused salts, and
of solutions of salts and acids, although less than that of metals, is
very great compared with the traces of conductivity found in so-called
non-conductors. In fused salts and conducting solutions the passage of
the current is always accompanied by definite chemical changes; the
substance of the conductor or electrolyte is decomposed, and the
products of the decomposition appear at the electrodes, i.e. the
metallic plates by means of which the current is led into and out of the
solution. The chemical phenomena are considered in the article
ELECTROLYSIS; we are here concerned solely with the mechanism of this
_ele