Electric light by the first practical electric arc light in 1806. By the 1870s, Davy's arc lamp had been successfully commercialized, and was used to light many public spaces. The development of a steadily glowing filament suitable for interior lighting took longer, but by the early twentieth century inventors had successfully developed options, replacing the arc light with incandescents. The energy efficiency of electric lighting has increased radically since the first demonstration of arc lamps and the incandescent light bulb of the 19th century. Modern electric light sources come in a profusion of types and sizes adapted to many applications. Most modern
President of the Royal Astronomical Society President of the Royal Astronomical Society The President of the Royal Astronomical Society (prior to 1831 known as President of the Astronomical Society of London) chairs the Council of the Royal Astronomical Society (RAS) and its formal meetings. They also liaise with government organisations (including the Department for Business, Innovation and Skills and the UK Research Councils), similar societies in other countries, and the International Astronomical Union on behalf of the UK astronomy and geophysics communities. Future presidents serve one year as President Elect before succeeding the previous president. There have been 89 RAS presidents . The first president was