A form of static influence machine. It consists of two plates of glass,
on which radial sectors of tinfoil are pasted. Both plates are rotated
in opposite directions. The sectors of the two plates react one upon the
other, and electric charges of opposite sign accumulate on the opposite
sides of the plates and are collected therefrom by collecting [...]

A modification of the Holtz machine. The priming charge of the armatures
is produced by friction of metallic brushes against metallic buttons on
the face of the rotating plate. (See Machine, Holtz.)

A static electric machine. It includes two plates, one of which is
rapidly rotated in front of the other. Two armatures of paper are
secured to the back of the stationary plate at opposite ends of a
diameter. To start it one of these is charged with electricity. This
charge by induction acts through the two thicknesses of glass [...]

A static electric machine working by induction to build up charges of
opposite nature on two separate prime conductors. In general they are
based on the principle of the electrophorous. Work is done by the
operator turning the handle. This rotates a disc and draws excited parts
of it away from their bound charges. This represents a resistance to
mechanical [...]

An apparatus for development of high tension electricity by contact
action, brought about by friction.
It consists of a plate or cylinder of glass mounted on insulating
standards and provided with a handle for turning it. One or more
cushions of leather are held on an insulated support, so as to rub
against the plate or cylinder as it is [...]

A frictional electric machine whose rotating glass is in the shape of a
cylinder instead of a disc as in the more recent machines.

(a) Symbol of gaseous pressure equal to one-millionth of an atmosphere.
(b) The Greek m, µ, is used as the symbol of magnetic permeability.
333   STANDARD ELECTRICAL DICTIONARY.