Alessandro Cruto Italian inventor Date of Birth: 25.05.1847 Country: Italy

1. Biography of Alessandro Cruto
2. Early Life and Education
3. Invention of Graphite Filaments
4. Improvement of Incandescent Lamps
5. Recognition and Legacy

Biography of Alessandro Cruto

Alessandro Cruto, an Italian inventor, was known for improving Thomas Edison's incandescent lamps. However, it is known that when he started, he dreamed of finding a way to produce diamonds.

Early Life and Education

Alessandro Cruto was born on May 25, 1847, in the village of Piossasco, Italy, into a family of builders. He studied at the School of Architecture at the University of Turin and attended lectures on chemistry and physics. During these lectures, the extravagant idea of crystallizing carbon to obtain diamonds was discussed.

Invention of Graphite Filaments

In 1872, Cruto opened his own small workshop in his hometown, where he began experiments to produce pure carbon from ethylene. His efforts were partly rewarded in 1874 when he successfully obtained thin graphite sheets as a result of his experiments. Initially, the inventor still hoped to find a way to produce diamonds.

Improvement of Incandescent Lamps

After attending conferences by Galileo Ferraris on electric technologies and conducting experiments inspired by Thomas Edison, Alessandro began searching for good filaments for incandescent lamps. He discovered that carbon filaments treated with ethylene under high pressure and temperature acquired a positive temperature coefficient of resistance. Cruto's filament was produced by depositing graphite on thin platinum wires in the presence of gaseous hydrocarbons. The sublimation of platinum at high temperatures resulted in filaments made of ultra-pure graphite. Alessandro believed that his discovery could be used in incandescent lamps instead of carbonized bamboo fibers. He continued to improve his invention in 1880 at the physics laboratory of the University of Turin.

Recognition and Legacy

In 1882, Cruto participated in the Electricity Expo in Munich, where he gained recognition for his new technologically advanced "light sphere" that outperformed Edison's light bulb in terms of efficiency. Cruto's sphere emitted white light instead of the yellowish light of Edison's bulb. The inventor continued to celebrate his success at the International Turin Expo in 1884 and sold patents for his invention to France, Switzerland, Cuba, and the USA.

After such success and due to insufficient production capacity in Piossasco, Cruto decided to relocate his activities to a more suitable place. He chose Alpignano, where he founded a factory for the production of "light spheres" in 1885-1886. He managed the factory until 1889, and eventually, the production level reached 100 bulbs per day. The old Cruto factory changed ownership multiple times, eventually went bankrupt, and was purchased by Philips in 1927.

Cruto married at a relatively mature age and spent the rest of his life with his family and in his old laboratory. He continued his experiments on harnessing atmospheric electricity and invented an electric toy called "mosca elettrica" (electric fly).

Almost forgotten by everyone, Alessandro Cruto died on December 15, 1908, in Turin.