Unless the oxygen is previously accommodated in the solid solution, the eutectic freezes at 50 K.[3] The constituents of air were once known as "permanent gases", as they could not be liquified solely by compression at room temperature.
With sufficient compression, flow, and heat removal, eventually droplets of liquid air will form, which may then be employed directly for low temperature demonstrations.
The main constituents of air were liquefied for the first time by Polish scientists Karol Olszewski and Zygmunt Wróblewski in 1883.
Air is fed at high pressure (>75 atm (7,600 kPa; 1,100 psi)) into the lower column, in which it is separated into pure nitrogen and oxygen-rich liquid.
Liquid nitrogen is useful in various low-temperature applications, being nonreactive at normal temperatures (unlike oxygen), and boiling at 77 K (−196 °C; −321 °F).
This was based on a technology that was developed by Peter Dearman, a garage inventor in Hertfordshire, England to power vehicles.