Plant.
The apparatus for commercial manufacturing or technical works. An
electric lighting plant includes the boilers, engines and dynamos for
producing the current, and the electric mains and subsidiary apparatus.
Plant Electricity.
Electricity manifested by plant life. By means of a galvanometer
potential differences are found to exist in different parts of trees or
fruits. The roots and interior portions are negative, and the flowers,
smaller branches and fruit are positive.
In some cases a contraction of the tissue of plants can be produced by
an electric current. The sensitive plant and others exhibit this
phenomenon, exactly analogous to the action of muscular tissue.
Plate, Arrester.
In a lightning arrester the plate connected to the circuit. Sometimes
both plates are designated arrester plates.
Plate Condenser.
A static condenser having a flat plate of glass for dielectric. (See
Epinus' Condenser.)
Plate Electrical Machine.
A frictional electric machine, in which a circular plate of glass is
excited by friction with the cushions. It is the most recent type of
frictional machine and has superseded the old cylinder machines. In its
turn it is superseded by influence machines, really plate machines, but
not so termed in practice.
Plate, Ground.
In a lightning arrester, the plate connected to the earth.
Plate, Negative.
In a voltaic battery, either primary or secondary, the plate which is
unattacked by the oxygen or negative radical or element of the fluid. It
corresponds to the carbon plate in the ordinary voltaic battery, and is
the one charged with positive electricity.
Plate, Positive.
In a voltaic battery, either primary or secondary, the plate which is
dissolved or attacked by the oxygen or negative radical or element of
the fluid. It is the plate corresponding to the zinc plate in the
ordinary voltaic battery, and is the one charged with negative
electricity.
Plating Balance.
A balance or scales to which articles in an electroplater's bath are
suspended. A weight exceeding by a known amount that of the article as
immersed overbalances the article. When the plating is being deposited
as soon as it exceeds the excess of weight of the counterpoise the
balance tips, the article descends a little, the electric circuit is
broken and the plating ceases. Thus the plating is automatically stopped
when a predetermined amount of metal is deposited.