(under the class definition) Devices which are provided with a radioactive material, the radioactive properties of the material being utilized in the operation of the device.
(1) Note. In the patents in this subclass the radioactive property of the material must have some significance in the operation of the device. The mere use of a radioactive substance such as thorium on or in a cathode to render it electron emissive, the use of uranium stained glass, or other such uses of radioactive materials where the radioactive properties of the material are not involved in the operation of the device is not considered sufficient to cause classification of the device in this subclass.
SEE OR SEARCH CLASS
250, Radiant Energy,
381, and 382 for an invisible radiant energy responsive gas discharge device having a radioactive gas, a gas borne radioactive material or a radioactive source within the device to ionize the gas of the device.
