Page:Post--Dwellers in the hills.djvu/205

Rh turning inward was apparently travelling down. This delusion of grade is well known to the swimmer. It is the chiefest terror of great water. Expert swimmers floating easily in flood water have been observed to turn over suddenly, throw up their arms, and go down. This is probably panic caused by believing themselves caught in the vortex of a cone, from which there seems no escape, except by the impossible one of swimming up to its rim, rising on all sides to the sky.

In a few minutes El Mahdi was in the centre of the eddy, carried by a current growing always stronger. In this centre the water boiled, but it was for the most part because of a lashing of surface currents. There seemed to be no heavy twist of the deep water into anything like a dangerous whirlpool. Still there was a pull, a tugging of the current to a centre. Again I was unable to estimate the power of this drag, as it was impossible to estimate how much resistance was being offered by the horse.

In the vortex of the eddy the delusion of the vast cone was more pronounced. It was one