THE MARVEL OF A TIDE 313 



and with a final splash the liquid subsided in the helmet so that 

 I was able to catch my breath once more. The savage current 

 caught my lightly balanced body, swooped it in a great arc 

 nearly to the surface, swirled me towards the shore where it 

 slackened and let me drop again on the sand. 



Then I became aware that beyond the shelter of the crags 

 a great assortment of objects was floating by at a dizzy rate. I 

 had noticed them before but they had made no impression. Be- 

 tween the cliffs the current was barely perceptible except as 

 a cool back eddy from the main stream. Once more I tried to 

 breast the flow but was thrust back as if by a heavy hand. There 

 was a solidity to the pressure that was unequaled by any other 

 flow of energy with which I have had experience. Wind in a 

 violent storm pushes and buffets one about, but water moving 

 at one-twentieth the speed of a gale of wind would level 

 everything in its path and tear up the ground besides. 



The sand out in the swath of the tide was moving too. Close 

 to the bottom the grains were rolling and bumping, creating 

 small dust storms— a strange phenomenon under water— and 

 long curving ridges and valleys a foot or more in depth which 

 formed in endless parallel arcs at right angles to the course of 

 the water. On a larger scale they were precisely like the smaller 

 ripples seen on the mud bars when the tide is out. The whole 

 ocean bottom seemed on the move, as though it were alive and 

 were creeping towards an unknown destination. 



Crouching in the shelter of the outermost boulder, I made 

 myself comfortable and sat down to contemplate this stupen- 

 dous event. For it was exactly that. All along the hundreds of 

 miles of coast all over the world this same action was takinor 



o 



place. Great rivers of liquid were surging past thousands of 

 headlands into bays, creeks, rivers, and lagoons, over shallow 

 bars and in the hollows of deep channels, rolling countless sand 

 grains and bringing oxygen, food, life and death to millions of 



