This was good advice, and Matt proceeded to carry it out.
"I had thought of taking Cassidy's place again in an hour," he observed.
"No use," was the answer. "If we don't sight the boat within an hour, then the chances are that we have gone wide of her—perhaps left her behind. We'll sink into quieter waters and come up again when the storm has abated. Then we'll cruise around and do everything possible to locate Dick and Carl."
The captain drew up a chair and braced himself at the periscope table.
At the end of an hour night had fallen, closed in with the Stygian gloom of the clouds and tempest. From that on the periscope was useless, and even a lookout from the top of the conning tower was of no avail.
Cassidy descended, closing the hatch behind him. His face was long and ominous.
"This ends it till mornin', cap'n," said he.
"Exactly so, Cassidy," replied the captain; "but the case isn't hopeless, by any means." He whirled to a speaking tube. "Fill the tanks, Clackett," he ordered, "and descend to twenty yards. Shut off your engine, Gaines," he added through another tube; "we'll pass the night where we are, sixty feet down."
The orders were repeated back, and the Grampus began to sink. When the periscope ball was submerged an automatic valve closed the hollow mast against an inrush of water.
Down and down they went, slipping noiselessly into great depths. Cassidy turned on a light from the storage batteries and an incandescent bulb flooded the periscope room.