Improvements in or connected with Means or Apparatus for Producing Radiation by Electricity

21,218. Stearn, C. H., and Topham, C. F. Sept. 24. R÷ntgen ray and like apparatus.-Lamps for producing light or R÷ntgen rays, by electric discharges in exhausted vessels falling on suitable anticathodes, are provided with means for automatically keeping the vacuum in any required condition. For producing light, the anticathodes are made of refractory earths, such as thorium oxide, either in compressed discs, or preferably several layers of fabric. In the form shown, such a body c is placed between two concave electrodes a, b, to which an alternating current is supplied. A lateral extension d of the exhausted vessel contains potassium chlorate or other material which gives off gas when sparks pass between electrodes inserted in it. These electrodes may be connected in parallel with the main electrodes a, b, an adjustable resistance e being included in the circuit so that, when the vacuum becomes too high, discharge takes place in the extension d ; or an electromagnetic relay in the main circuit may send current through the extension.