Incandescent light bulb granted a Hungarian patent (No. 34541) for a tungsten filament lamp that lasted longer and gave brighter light than the carbon filament. Tungsten filament lamps were first marketed by the Hungarian company Tungsram in 1904. This type is often called Tungsram-bulbs in many European countries. Filling a bulb with an inert gas such as argon or nitrogen slows down the evaporation of the tungsten filament compared to operating it in a vacuum. This allows for greater temperatures and therefore greater efficacy with less reduction in filament life. In 1906, William D. Coolidge developed a method of making "ductile tungsten" from
Hammer Historical Collection of Incandescent Electric Lamps William Joseph Hammer started to collect incandescent light bulbs from 1879 while they were being developed in the Edison laboratory in Menlo Park, New Jersey. He was an associate of Thomas Edison and in his engineering career he was able to collect early filament electric light bulbs from Edison and others because of his association in the field. The Hammer collection is the most comprehensive collection of incandescent electric light bulbs known in the world. It shows the technology development of the filament electric light bulb during Thomas Edison's lifetime. Hammer's incandescent light bulb collection from around the world was