Cheaper Protection

Helium is non-inflammable and lessens the risk of airship operation. But it costs $100 per 1,000 cubic feet and--in spite of the goldbeater's skin covering the cotton bags--it leaks out to the tune of several hundred dollars a day. The British Air Secretary now announces a different scheme, whereby cheap hydrogen will be surrounded with a shell of inert gas, minimizing fire risk at a tenth of the cost of helium.