"You three," ordered the captain, indicating Moy, Banks, and Smithers. "Keep your knives in your hands and don't hesitate to use them. Take a charge of guncotton. If you've a chance place it under her bilges, and I'll take the risk of blowing this infernal submarine to Jericho."

Quickly the three dauntless divers prepared to descend, while a petty officer and two seamen hastened to bring the explosive from the magazine and the batteries for firing the charge.

But ere the divers were ready a sudden commotion on shore attracted the attention of Captain Tarfag and the crew of the "Investigator." The working party on the beach had discovered that the net entanglements no longer held. They were coming home with hardly any resistance, bringing with them the grapnels of the picquet-boats till the latter had to hastily cast off in order to prevent themselves being dragged ashore.

"She's given us the slip, by George!" ejaculated Mr. Egmont.

"Perhaps the nets have parted," suggested Captain Tarfag. "Look alive, men!"

One after another the divers disappeared over the side. Three distinct patches of bubbles indicated their course. They were, for mutual safety, keeping close together. To all inquiries on the telephone the answer was, "Nothing to be seen," until Moy reported that he had discovered distinct traces in the sand of the impression of a fairly flat-bottomed vessel of at least thirty foot beam.

"It's no go," exclaimed Captain Tarfag. "Order the men back, and report the loss of Mr. Hythe and O' Shaunessey to the Commander-in-Chief at Devonport. By smoke! All the fat is in the fire now."

Quickly the dispiriting news spread from ship to ship, and from boat to boat. A panic seemed to seize the spectators in private craft, for, as if by a sudden impulse, they made a wild stampede from the shelter of the shallow water of Cawsand Bay. But nothing happened to imperil their safety. No huge sea-monster, the work of human hands, appeared to scatter destruction broadcast upon those venturesome individuals who had gone forth to witness the capture of the mysterious Captain Restronguet. The elusive submarine had calmly stolen away, without a trace of the tragedy that every one imagined had been enacted beneath the waves, save for portions of the two life-lines and the disconnected air-tubes.

The "Investigator" and the rest of the Government vessels lost no time in putting into the Hamoaze. Captain Tarfag, accompanied by Lieutenant Egmont, immediately went on shore to report to the Commander-in-Chief. Already special editions of the papers were out, giving more or less accurate accounts of the futile operations in connexion with the attempt to capture the submarine, and all laid particular stress upon the fact that the lives of an officer and a seaman had been sacrificed on the altar of duty.

"You saw nothing, Tarfag?" asked the Admiral.