液氧
The development of uses in refrigeration also enabled advances in air conditioning and the liquefaction of gases. Carbon dioxide was first liquefied in 1823. The first Vapor-compression refrigeration cycle using ether was invented by Jacob Perkins in 1834 and a similar cycle using ammonia was invented in 1873 and another with sulfur dioxide in 1876. Liquid oxygen and Liquid nitrogen were both first made in 1883; Liquid hydrogen was first made in 1898 and liquid helium in 1908. LPG was first made in 1910. A patent for LNG was filed in 1914 with the first commercial production in 1917.