After the tungsten filament

By the end of the first World War, it must have seemed that the development of electric lighting had reached its peak. Tungsten filament lamps were firmly established as the best light for most purposes, even though arc lamps were still widely used out of doors. Other ways of making light were also being investigated, though none were as simple and convenient as filament lamps. Most promising were the gas discharge lamps, especially those using mercury vapor. This paper discusses the laboratory research in London on discharge lamps including the gas, glass and quartz used in the lamps. The wire heating elements used in such lamps are also discussed.