Each morning I walked up the beach to the chasm, sometimes alone and sometimes accompanied by Mr. Millward. In two days the breakwater at the exit was completely covered with sand, which rose above the level of high tide, and the sand had already begun to silt into the chasm back of the exit. On the third day we found a great shark embayed in the chasm and dashing around the old hull every little while, as though in a flurry of excitement. Each time a wave would break in he would endeavor to swim out, following the retreating water,--for now there was no longer a current through,--but the trees and limbs prevented him. Mr. Millward said he seemed like an evil spirit set to guard the galleon and its treasure; and indeed it would have been a dangerous thing for any one to attempt exploration of the wreck while this man-eating sentinel patrolled the narrow water where she lay.
The sight of this voracious fish reminded me very forcibly of the great danger which would have attended any attempt to reach the hull by diving when the galleon lay out in the sea. Had I brought my diving-apparatus safely to the island, as I originally intended to do, it is quite possible, and even probable, that I should have found a grave among the gastric fluids of some such shark. Strangely enough, in all the many times I had looked at the wreck through the water-glass while it lay out in the sea, I had never seen a single shark, though other fish had been visible in considerable numbers and variety. But doubtless, as is the treacherous nature of this tiger of the sea, he was lying there concealed and instinctively watching the boat in expectation of prey. It made me shudder involuntarily to think of the possible encounter that I might have had. As the shark imprisoned in the chasm was no present inconvenience to us, we allowed him to remain undisturbed where he was.
As we stood on the rock which adjoined the shore, watching the frothing of the surges through the breakwater at the mouth of the chasm, I pointed out to Mr. Millward that every few minutes, at intervals of about every third wave, the water rushing back met the incoming wave exactly at the breakwater and the resulting interference produced there a temporary quiet in the waters.