The captain was continually watching the horizon with his glasses, and he talked to Robert less than usual.

It was obvious that he felt anxiety.
The calm was broken just before nightfall.

Dark had come with the suddenness of the tropic seas.

There was a puff of wind, followed by a steady breeze, and the schooner once more sped southward.

Robert, anxious to breathe the invigorating air, came upon deck, and standing near the mainmast watched the sea rushing by.