the surface of the waves—­hidden pitfalls of death whose yawning jaws threatened instant destruction to the unwary voyager.  The splendid steamer Cowarra had been wrecked on these reefs only a few months before, but a single one of her two hundred and seventy-five passengers escaping a watery grave.  Her tall masts, still standing bolt upright amid the coral-reefs, presented a gaunt spectacle, plainly visible from the Hero’s decks as she threaded her way among the shoaly waters, while a similar though less tragical warning was the disaster that had overtaken two other vessels, the Astrolabe and the Zelee, which by a sudden ebb of the tide were thrown high and dry upon the sands, and remained in this frightful condition for eight days before the returning waters drifted them off.  But the Hero was a staunch craft—­an iron blockade-runner, built at Glasgow during our late war.  She was of twelve hundred tons burden, manned by forty-two men, and had already weathered storms and dangers enough to earn a right to the name she bore.  Right nobly she fulfilled her dangerous mission, threading her way with difficulty among whole fields of coral, that sometimes almost enclosed her low hull as between two walls; again seeming upon the very verge of the breakers or ready to be engulfed in their whirling eddies, but emerging at last into the open channel, a monument of the skill and watchfulness of her officers.  Many of these for days together never left the deck, and the lead was cast three or four times an hour during the whole passage of these dangerous seas.  Such is the history of navigation in coral seas, but if full of danger, they are equally replete with picturesque beauty.  In the coral isle, with its blue lagoon, its circling reef and smiling vegetation, there is a wondrous fascination; while in the long reefs, with the ocean driving furiously upon them, only to be driven pitilessly back, all wreathed in white foam and diamond spray, there is enough of the sublime to transfix the most careless observer.  The barrier reef that skirts the north-east coast of the Australian continent is the grandest coral formation in the world, stretching for a distance of a thousand miles, with a varying breadth of from two hundred yards to a mile.  The maximum distance from the shore is seventy miles, but it rarely exceeds twenty-five or thirty.  Between this and the mainland lies a sheltered channel, safe, for the most part, when reached; but there are few open passages from the ocean, and the shoals of imperfectly-formed coral that lie concealed just below the surface render the most watchful care necessary to a safe passage.  The fires of the cannibals, visible on every peak all along the coast, shed their ruddy light over the blue waters, illumining here and there some lofty crest, and adding a weird beauty to the enchanting scene.

[Illustration:  Monument to Burke and Wills.]