When were cryogenics invented?

Cryogenics as a field emerged in the mid-20th century, but the principles underlying it date back to the late 19th century. The first successful liquefaction of gases, a key development for cryogenics, occurred in 1877 when hydrogen was liquefied by James Dewar. The term "cryogenics" itself was coined in the 1940s, as scientists began to explore the effects of extremely low temperatures on materials and biological systems.