At the same instant he caught a cry:
“Help! Help!”
It appeared to come from far astern.
“Joe!” shouted Nat into the darkness.
“Help!” came the cry again. It was closer this time.
A coil of light but strong rope was looped to the bridge in front of Nat. Without an instant’s hesitation, he tied one end of it about his waist. He had reached a desperate determination. If he got a chance, he had made up his mind to save Joe Hartley if it were humanly possible. The other end of the coil he knew was made fast to the bridge rail, so that a final testing of the knot about his waist was all that was necessary to put his daring scheme into execution. But first Nat fixed the wheel by means of the metal grips provided for that purpose.
Then, with every nerve a-quiver, every muscle flexed, he waited for another summons. Suddenly it came.
“Help, Nat! I——”
A smother of foam swept glimmering past the Nomad. It was luminous with phosphorescence. Amidst the greenish, ghastly glare, was plainly perceptible a darker spot. It was a human head.
“Hold on, Joe! I’ll be with you!” shouted Nat, and then, without hesitation, he mounted the bridge rail at the port side and plunged into the mass of spume.