An oscillation of current in open circuit so that a spark discharge
accompanies it. It is produced by electric resonance in a simple circle
or loop of wire with ends placed near together but not touching, if the
circuit is of such size that its period of oscillation corresponds with
that of the inducing discharge. (See Resonance, Electric.) Its [...]

An electric circuit is said to be open when it is cut or broken so that
no current can pass through it. The term may be recollected by thinking
of a switch; when open no current can pass through it. The same
adjective is applied to magnetic circuits, an air gap implying an open
circuit.

A compound gas; C2H4; composed of carbon, 24; hydrogen, 4; molecular
weight, 28; specific gravity, .981.
It is a dielectric of about the resistance of air. Its specific
inductive capacity at atmospheric pressure is 1.000722 (Boltzman.)
Synonym–Ethene; heavy carburetted hydrogen.
[Transcriber's note: Also called ethylene. A primary use is polyethylene
plastic.]

Oil insulation has received several applications in electrical work. It
has been proposed for use in underground conduits. These it was proposed
to fill with oil after the insertion of the conductors, the latter
properly wrapped with cotton or other covering. For induction coils it
has been very successfully used. Its principal utility depends on the
fact that it is [...]

The true ohm is the resistance of a column of mercury 1 square
millimeter in cross-sectional area, and 106.24 centimeters long. (See
Ohm.)
Synonym-Rayleigh Ohm.

The fundamental law expressing the relations between current,
electro-motive force and resistance in an active electric circuit. It
may be expressed thus:
(a) The current strength is equal to the electro-motive force divided by
the resistance.
(b) The electro-motive force is equal to the current strength multiplied
by the resistance.
(c) The resistance is equal to the electro-motive force divided by the
current [...]

An instrument for measuring directly the resistance of a conductor or of
any part of a circuit through which a strong current is passing.  It is
the invention of Prof. W. E. Ayrton.
It contains two fixed coils at right angles to each other acting on the
same needle of soft iron. One coil is of thick wire and [...]

The practical unit of resistance. The resistance of a column of mercury
one square millimeter in cross-sectional area and 106 centimetres long
at 0º C. (32º F.) The ohm used previously to 1884 is the B. A. Unit of
Resistance, q. v.
One legal ohm = 1.0112 B. A. Units, and I B. A. Unit = 0.9889 legal ohm.
The [...]

True resistance as distinguished from spurious resistance, or
counter-electro-motive force.

The approximate ohm as recommended by the British Board of Trade on the
advice of a committee (Sir W. Thomson, Dr. J. Hopkinson, Lord Rayleigh
and others). It is the resistance of a mercury column one square
millimeter in section, and 106.3 centimeters long at 0º C. (32º F.)
Synonym–New Ohm.