The lines in Craig's face deepened in thought as he folded the message and remarked abstractedly, "She works all right when you are aboard." Then he recalled himself. "Let us try her again without a crew."
Five minutes later we had ascended to the aerial conning-tower, and all was in readiness to repeat the trial of the night before. Vicious and sly the Z99 looked in the daytime as she slipped off, under the unseen guidance of the wireless, with death hidden under her nose. Just as during the first trial we had witnessed, she began by fulfilling the highest expectations. Straight as an arrow she shot out of the harbour's mouth, half submerged, with her periscope sticking up and bearing the flag proudly flapping, leaving behind a wake of white foam.
She turned and re-entered the harbour, obeying Captain Shirley's every whim, twisting in and out of the shipping much to the amazement of the old salts, who had never become used to the weird sight. She cut a figure eight, stopped, started again.
Suddenly I could see by the look on Captain Shirley's face that something was wrong. Before either of us could speak, there was a spurt of water out in the harbour, a cloud of spray, and the Z99 sank in a mass of bubbles. She had heeled over and was resting on the mud and ooze of the harbour bottom. The water had closed over her, and she was gone.
Instantly all the terrible details of the sinking of the Lutin and other submarines flashed over me. I fancied I could see on the Z99 the overturned accumulators. I imagined the stifling fumes, the strug-
