Instantly the officer set the needful machinery in motion, and silently the after tanks began to fill. The water was sucked in through the sea-valves, with hardly a sound, now that they were running where the pressure of the water was more intense. Fifty feet now showed upon the gauge. Lieutenant Parry scanned the chart in front of him, illuminated by a hooded light.

“We’ve got plenty of sea room under our keel,” he said; “the chart gives us 400 fathoms here. Lockyer, I’m glad, old man, for your sake, and for the sake of somebody else.”

“Thanks,” said Lockyer simply, and though they could not see his face, they knew that it softened as he thought of the girl who had christened his diving boat.

“Here, boys, come up in the conning-tower,” ordered the naval officer presently, “Mr. Stark and I want to take a look about below.”

So it came about that, presently, Ned had the wheel once more in his hands. “What’s the course, sir?” he inquired, as the officer relinquished the spokes.

“Two points north of west,” was the response; “keep her on it till further orders.”

Ned saluted, and the officer went below, leaving the young steersman, Herc, Tom Marlin, and Sim in the conning-tower.

It was an eerie, strange feeling, this, of steering such a craft through the inky expanse spread about. Viewed through the lenses of the tower, the blackness seemed almost solid. Through the inky depths the submarine, a blind, swift-moving monster, nosed her way. Not so swift-moving now though, for her speed had been slowed down to a bare ten miles.

“Well?” asked Ned, as the officers vanished in the wake of the inventor for an inspection of the engine room.

“Well?” sighed Herc, “how about you?”