He was about to touch the tank-lever when Barney from the deck, gave a sudden sharp cry:

“Whurroo, Misther Frank, shure, it’s a sail off to windward!”

“A sail?”

Frank and Wade gazed in that direction. Then both gave a violent start. A small schooner was seen bearing down upon the Diver.

Wade’s eyes dilated.

“It is the Meta!” he exclaimed; “they are making for us!”

This was the truth. Hardy Poole’s piratical schooner it was, and they had sighted the submarine boat.

She was bearing down rapidly, with all sails set. Frank and his companions watched the schooner with some curiosity.

But Frank knew that it would never do for the schooner to come within cannon shot. One ball striking the submarine boat would be likely to ruin her.

So he ran up a signal flag of defiance. It was seen by Poole, and a cannon was fired in reply.