“I did, captain,” answered Ayrton.

“And that was—”

“Four days ago.”

“Ah! a note!” cried Herbert, pointing to a paper lying on the table.

On this paper were written these words in English:—

“Follow the new wire.”

“Forward!” cried Harding, who understood that the despatch had not been sent from the corral, but from the mysterious retreat, communicating directly with Granite House by means of a supplementary wire joined to the old one.

Neb took the lighted lantern, and all left the corral. The storm then burst forth with tremendous violence. The interval between each lightning-flash and each thunder-clap diminished rapidly. The summit of the volcano, with its plume of vapor, could be seen by occasional flashes.

There was no telegraphic communication in any part of the corral between the house and the palisade; but the engineer, running straight to the first post, saw by the light of a flash a new wire hanging from the isolator to the ground.

“There it is!” said he.