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 have had exchange programs to replace incandescent bulbs with energy efficient versions. Ghana banned incandescent bulbs in 2008 and Senegal has banned the manufacture and import. Egypt is reported to have a partial ban on incandescent light bulbs. Kenya has a programme to exchange a number of light bulbs with more efficient types. Morocco has a programme to exchange a number of light bulbs with more efficient types. Namibia has an exchange program which distributed 1 million energy saving bulbs in 2016. Rwanda has an exchange program, distributing CFL bulbs. South Africa phased out incandescent light bulbs in 2016. Tanzania