I made my way back to the keel-boat with this information, and the laboring engine began to chug even while I was briefly explaining the situation to Rene.

She listened almost wearily, asking but few questions, and both of us soon lapsed into silence.

A little later she had pillowed her head on her arms and apparently had fallen asleep.
I must have dozed, myself, as the hours passed, although hardly aware of doing so.

The soft, continuous chugging of the engine, the swash of water alongside, the ceaseless sweep of the current, and the dark gloom of the shadows through which we struggled, all combined to produce drowsiness.

I know my eyes were closed several times, and at last they opened to a realization that gray, sickly dawn rested upon the river surface.