(under the class definition) Devices having a filament and an additional body other than an electrode designed to be heated to incandescence by the filament.
(1) Note. The body designed to be heated to incandescence is not designed to be connected in the circuit in anyway but is designed only to be a light emitting body.
SEE OR SEARCH THIS CLASS, SUBCLASS:
14, for pyroelectric type electric lamps which include a body designed to be heated from a separate source such as an electric filament. The body being a second class conductor and being connected in the circuit so that when heated it will conduct electric current and be heated by the current flowing through it.
305+, and the subclasses specified in the notes thereto for discharge devices which have an electrode which is designed to be heated to incandescence by the electric space discharge between the cathode and the electrode.
