During the 1850s, Ferdinand Carre of France developed a second type of refrigeration machine. In his system, the refrigerant (normally a vapor) is absorbed in a suitable liquid. This solution is heated, driving off the refrigerant as a vapor, which then is condensed. Evaporation of the liquid produces the desired cooling. The refrigerant vapor is absorbed again in the liquid, thus completing the cycle. In 1859, Carre introduced ammonia as the refrigerant with ammonia-water as an absorbent. The successful combination was used throughout the world.