He knows enough, the mariner, who knows
Where lurk the shelves, and where the whirlpools boil,
What signs portend the storm: to subtler minds
He leaves to scan, from what mysterious cause
Charybdis rages in the Ionian wave;
Whence those impetuous currents in the main
Which neither oar nor sail can stem; and why
The roughening deep expects the storm, as sure
As red Orion mounts the shrouded heaven.