“Imagine a sphere,” he explained, “large enough to hold two people and their luggage. It will be made of steel lined with thick glass; it will contain a proper store of solidified air, concentrated food, water-distilling apparatus, and so forth. And enamelled, as it were, on the outer steel⁠—”

“Cavorite?”

“Yes.”

“But how will you get inside?”

“There was a similar problem about a dumpling.”

“Yes, I know. But how?”

“That’s perfectly easy. An airtight manhole is all that is needed. That, of course, will have to be a little complicated; there will have to be a valve, so that things may be thrown out, if necessary, without much loss of air.”