He remained in thought for some moments, then rose.
"P'r'aps you're right," he remarked drowsily. "Very likely they're only harmless Dagos after all. I'm going to turn in, so clear out!"
And a few moments later Lieutenant Lawless was sleeping.
On the following morning Lawless noticed that the Black Diamond left her berth and steamed down the river about an hour before the Mars and her escort were due to leave.
"Well, your nightmare's ship's gone now," remarked Trent. "One of the port officials told me she had cleared for Valencia with coals."
"Coals!" echoed Lawless. "Rum sort of place to ship coals for the Mediterranean! They could get it cheaper and quicker at Cardiff and Newport, besides saving about four days on the double trip."
Soon afterwards came the signal to get under way. The Mars was to proceed at about ten knots, with the Arrow and Kite astern on each side, and the Knat in front to act as scout and clear the way for her.
Slowly and majestically the marine monster—the latest triumph of death-dealing mechanism—swung down the river, her convoy of destroyers looking no larger than midges against her huge bulk. Evening was drawing in as they came abreast of the white light on Cambrae Island, and, although he had been keeping a careful look-out all the afternoon, Lawless had seen nothing of the mysterious Black Diamond.
"It's strange!" he mused. "I can't understand it."
An hour or two later, when darkness had set in, Lawless left Trent in charge and went below to snatch a little rest. He had hardly been in his bunk ten minutes, when a messenger knocked at the cabin door and informed him that he was wanted on the bridge.