THE temperature range between about 25 and 28 ยฐ K may be covered with.liquid neon by means of normal cryostats, and up to about 42ยฐK by using pressure cryostats. In addition to being completely free from danger in its behaviour, liquid neon has the advantage of a heat of evaporation per cubic centimetre three times as large as that of hydrogen. There is little doubt, therefore, that it will be applied in the near future as a cooling agent for many purposes; this, in fact, has already been suggested. I
Neon is a by-product recovered in helium production from helium-neon mixtures, and is obtained in airseparation plants. This kind of helium production can be applied to large quantities in a very economic manner. 2'3 However, up to now only low output plants have been described for the separation of this mixture. These are based on the condensation method 4'5 as well as on the adsorption method, 5-7 and are operated discontinuously-which is neither convenient nor economic.
A simple plant will be described which produces neon of high purity and usable raw helium in a continuous operation and with low power requirement.