A Review of the Helium Question: A Comprehensive Survey of its Properties, Sources of Supply and Possibilities for Use in Airships

WHILE owing to helium's absence of chemical affinities it might at first sight be imagined that its separation from a mixture of other gases could best be carried out by effecting chemical changes in the latter, in only a very few cases is this a practical procedure. Indeed, at the present time all helium, which is being recovered from natural gas, is obtained by physical means.