"'The gas is expanding,' he explains, 'it's the sun that's doing it.
If we don't let some gas out we'll bust.'
"And if we do we'll drop into the sea," says I.
"'Yes, that's very likely,' he replied, as cool as a cucumber, 'when the evening comes and the gas condenses, with what we've lost, if we pull the valve open, we won't have enough to keep the ship in the air.'
"'There's only one thing to do,' he went on, 'we must wait till this ship I've been speaking to by wireless comes in sight. Then we'll take a chance. If the worst comes to worst we can float about till they pick us up.'
"That seemed a good plan to me and I never gave the sharks a thought. But when you drew near and it seemed as if the bag was going to bust in a second's time and we tried to open the valve—we couldn't. The halliards that work it had got twisted in the gale that blew us out to sea and they wouldn't come untangled.
"Melville takes a look at the pressure gauge. Then he gave a long whistle.
"'If we don't do something she'll bust in five seconds,' he says.
"Then I suddenly made up my mind. Without saying a word to him I kicked off my boots and started to climb into the rigging.
"'What are you going to do?' asked Melville.
"Open that valve, says I.