“All same stone in our country,” added Tuesday.

Lake stared at them with a dropped jaw. It was plain to see he was astonished.

“You’ve crossed by this stone?” he asked sharply.

But Monday shook his head.

“No,” he said, “but some time we come here and rock on him.”

For some reason or other Bully Banjo seemed mightily relieved at this.

“Waal,” he said, “it’s a simple thing, arter all. Jes’ a matter of balance. But I tell yer it took nerve ther first time me an’ Zeb crossed over, although we knew the rock would work—at least, the sealer wot told us about ther mine told us that ther thing was safe. And now, perfesser, ef you’ve no objection, we’ll jes’ send one of yer blacks across since they’re used ter it, an’ when they land safe on the ledge it’ll give ther rest of you courage.”

“Monday, do you mind attempting this?” asked the professor. The kind-hearted scientist would rather have tried the experiment himself—risky as it seemed—than compel one of his servants to go unwillingly. But he was under no such compulsion. Monday gave a broad grin that showed his white teeth in an expression of almost childish pleasure.

“Me like go, boss,” he said.

“All right, then. Up with yer,” ordered Lake brusquely. “I don’t want ter fool away too much time hyar, but I jes’ had ter know about thet gold afore we sail.”