Olefiant Gas.
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.]
Open. adj.
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.
Open Circuit Oscillation.
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 period
depends entirely on the self-induction of the circuit.
Ordinate.
In a system of plane co-ordinates (see Co-ordinates), the distance of
any point from the axis of abscissas measured parallel to the axis of
ordinates.
Ordinates, Axis of.
The vertical axis in a system of co-ordinates, q. v.
Synonym--Axis of Y.
Organ, Electric.
An organ in which the air blast is admitted or excluded from the
different pipes by electric mechanism.
The outlines of the system are a series of contacts worked by the keys
and stops, which cause, when operated by the organist, a current to pass
through electro-magnets, opening the valves of the different pipes. Thus
the manual may be at any distance from the organ, and a number of organs
may be worked upon the same manual. As many as five in a single
cathedral are thus connected to a manual in the chancel.
Orientation of a Magnetic Needle.
The acquirement by a magnetic needle of its position of rest, with its
magnetic axis in the magnetic meridian.
Origin of Co-ordinates.
In a system of linear co-ordinates the point of intersection of the
axes; the point whose co-ordinates are both zero.