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,
Kerosene lamp of combustion lighting are a continuing concern in many countries. Flat-wick lamps have the lowest light output, center-draft round-wick lamps have 3–4 times the output of flat-wick lamps, and pressurized lamps have higher output yet; the range is from 8 to 100 lumens. A kerosene lamp producing 37 lumens for 4 hours per day consumes about 3 litres of kerosene per month. 12.57 lumens = 1 CP Kerosene lamp A kerosene lamp (also known as a paraffin lamp in some countries) is a type of lighting device that uses kerosene (paraffin) as a fuel. Invented by the Polish pharmacist Ignacy