The march of the troops through the corridor was as rapid as was consistent with the number of men that moved through so narrow a passage, but it was not ample to permit us to gain appreciably on the pursuing tide. As the level of the passage rose, so, too, did the waters rise until it soon became apparent to me, who brought up the rear, that they were gaining rapidly upon us. I could understand the reason for this, as with the narrowing expanse of Omean as the waters rose toward the apex of its dome, the rapidity of its rise would increase in inverse ratio to the ever-lessening space to be filled.
Long ere the last of the column could hope to reach the upper pits which lay above the danger point I was convinced that the waters would surge after us in overwhelming volume, and that fully half the expedition would be snuffed out.