There must be land to the eastward, though nothing but the spinning mill is visible.  The land is below the level of the sea.  There is probably an entrance to some canal behind the moving sandbank.  This is one of the waste-places of the world—­a place left clean on sailors’ charts; no one passes that way.  These banks are as deadly as many rocks which have earned for themselves a dreaded name in maritime story.  For they never relinquish anything that touches them.  They are soft and gentle in their embrace; they slowly suck in the ship that comes within their grasp.  Their story is a long, grim tale of disaster.  Their treasure is vast and stored beneath a weight, half sand, half water, which must ever baffle the ingenuity of man.  Fog, the sailors’ deadliest foe, has its home on these waters, rising on the low-lying lands and creeping out to sea, where it blows to and fro for weeks and weeks together.  When all the world is blue and sunny, fog-banks lie like a sheet of cotton-wool on these coasts.

“Barrin’ fogs—­always barrin’ fogs!” Captain Cable had said as his last word on leaving the Signal House.  “If ye wait a month, never move in a fog in these waters, or ye’ll move straight to Davy Jones!”

And chance favored him, for a gale of wind came instead of a fog, one of those May gales that sweep down from the northwest without warning or reason.

At sunset the Olaf had crept cautiously in from the west—­a high-prowed, well-decked, square-rigged steamer of the old school, with her name written large amidships and her side-lights set aft.  Captain Petersen was a cautious man, and came on with the leadsman working like a clock.  He was a man who moved slowly.  And at sea, as in life, he who moves slowly often runs many dangers which a greater confidence and a little dash would avoid.  He who moves slowly is the prey of every current.

Captain Petersen steamed in behind the beacon.  He sighted the windmill very carefully, very correctly, very cautiously.  He described a half-circle round the bank hidden a few feet below the muddy water.  Then he steamed slowly seawards, keeping the windmill full astern and the beacon on his port quarter.  When the beacon was bearing southeast he rang the engine-room bell.  The steamer, hardly moving before, stopped dead, its bluff nose turned to the wind and the rustling waves.  Then Captain Petersen held up his hand to the first mate, who was on the high forecastle, and the anchor splashed over.  The Olaf was anchored at the head of a submarine bay.  She had shoal water all round her, and no vessel could get at her unless it came as she had come.  The sun went down, and the red-gray clouds in the stormy west slowly faded into night.  There was no land in sight.  Even the whirligig windmill was below the horizon now.  Only the three-legged beacon stood near, turning its winking, wondering eye round the waste of waters.

Here the Olaf rode out the gale that raged all through the night, and in the morning there was no peace, for it still rained and the northwest wind still blew hard.  There was no depth of water, however, to make a sea big enough to affect large vessels.  The Olaf rode easily enough, and only pitched her nose into the yellow sea from time to time, throwing a cloud of spray over the length of her decks, like a bird at its bath.