Alessandro Cruto

Alessandro Cruto was an Italian inventor, born May 24, 1847 in Piossasco and died December 15, 1908 in Turin, who developed one of the earliest successful incandescent lamp filaments while pursuing an unrelated dream of manufacturing artificial diamonds from crystallized carbon. Studying architecture alongside physics and chemistry courses at the University of Turin, he opened a workshop in Piossasco in 1872 to research carbon production and by 1874 had produced graphite sheets; continuing the work, he found that a carbon filament treated with ethylene gas under high pressure and temperature gained a positive resistance coefficient and produced a whiter, more efficient light than the yellowish glow of the carbon filament lamps Thomas Edison was making at the same time. He demonstrated the lamp in the physics laboratory of the University of Turin in 1880 and won recognition for it at the 1882 Electricity Exposition in Munich and the 1884 Turin International Exposition, then opened a light bulb factory in Alpignano in 1885 that was producing about a thousand bulbs a day before management disagreements pushed him out of the business in 1889. The Alpignano factory was later acquired by Philips in 1927, and Cruto himself died largely forgotten despite the real technical advance his filament represented.