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
Phase-out of incandescent light bulbs media outlets and industry forums, and he was invited as one of six experts to testify before the U.S. Senate Committee on Energy and Natural Resources on 11 March 2011. CFLs, like all fluorescent lamps, contain small amounts of mercury, as both vapor and droplets inside the glass tubing, averaging 4.0 mg per bulb. The inclusion of liquid mercury is specifically prohibited from other domestic products in some jurisdictions, notably Europe. Safe cleanup of broken compact fluorescent lamps is different from cleanup of conventional broken glass or incandescent bulbs. After a proper cleanup, any potential short term exposure offers no