“Still, a man need not be stingy all round,” said Trane. He was thinking of Egholm’s bald pate and untouched beard, that rendered him independent of all the barbers in the world.

“Here, Rothe,” said the Doctor. “Come and explain the thing. How’s it supposed to work? I’ve seen plans and drawings of that sort, of course, but I don’t mind admitting it’s altogether beyond me.”

“Oh,” said Rothe, shrugging his shoulders and puckering his brows with a careless air, “it’s not so easy to explain when you’re not in the business. But, roughly, it’s like this....” And he began setting forth briefly the principles of the turbine.

“And that, of course, can only go round one way. How he’s ever managed to get it to reverse, the Lord only knows. There’s nothing much to see from the outside.”

“Well, we shall hear this evening how it works.”

“Perhaps—perhaps not. I shouldn’t be too certain. There’s a heap of things to take into consideration, apart from what you might call the principle of the thing.”

“How do you mean?”

“Well, you wouldn’t see it, of course, but there’s a hundred odd things. That boiler there, for instance—can he get up a sufficient head of steam with that? I don’t believe it. A turbine wants any amount of steam to drive. If he got it fairly going, the thing’d simply burst. Hark! how it’s thumping away already. But there’s no danger as long as he’s only got that dolls’ house grate to heat it with. And as for the boat”—Rothe looked round to make sure that Lange was out of hearing; the others were limping back shiveringly to land—“the freckle-nosed birch-and-ruler merchant’s right enough; it’s simply falling to pieces as it is. Egholm, poor devil, he got some odd bits of tin from my place and patched up the worst parts, but the nails wouldn’t hold even then.—Coming off, Doctor? Here, get up again.—And the stuff he’s burning’s no better than hay. He’s been stoking away for a couple of hours now, and hasn’t got up steam yet.”

“What d’you reckon it would cost to make the experiment properly?” asked the Doctor, with his expressionless face, as they reached dry land again.