Thomas Edison of the Edison patent to charge a more reasonable rate for the use of the Edison patent rights and lowering the price of the electric lamp. On October 8, 1883, the US patent office ruled that Edison's patent was based on the work of William E. Sawyer and was, therefore, invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose British patent had been awarded a year before Edison's,
Banker's lamp Banker's lamp The banker's lamp (or Emeralite) is a style of electric table lamp characterised by a brass stand, green glass lamp shade and pull-chain switch (though modern versions may make use of alternate switch types). Other examples can feature different colors of glass. The first patent for a banker's lamp was filed on 11 May 1909 by Harrison D. McFaddin and were produced and sold under the brand name Emeralite ("emerald" and "light"). Emeralite lamp shades were produced by the J. Schreiber & Neffen factory located in the city of Rapotín, Moravia. Later competitors were sold as "Greenalite", "Verdelite"