It was known since experiments of Antoine Lavoisier that diamond was a form of carbon.Wells's story appeared a few years after the claims of James Ballantyne Hannay in 1879 and Ferdinand Frédéric Henri Moissan in 1893, that they had made artificial diamonds. Moissan heated charcoal (a form of carbon) and iron in a furnace until the iron melted; then rapidly cooled, the iron would generate high pressure and transform the charcoal into diamonds. Others tried to repeat this experiment in later years, and very small diamonds were created; commercially successful production of synthetic diamonds was not achieved until the 1950s.