Liquid hydrogen

A new technique enabled the production of liquid hydrogen at very low temperatures. This was a significant advancement in gas liquefaction processes. However Helium remained a gas even at 20°K.
Carl von Linde Germany 1898
Liquid hydrogen

A new technique enabled the production of liquid hydrogen at very low temperatures. This was a significant advancement in gas liquefaction processes. However Helium remained a gas even at 20°K.