Read it through once

Fully to realize the marvelous precision required in laying the great steamer in her marks in that murky waste of water, one should know that not only must she pick her intricate way through snags and blind reefs, and then shave the head of the island so closely as to brush the overhanging foliage with her stern, but at one place she must pass almost within arm's reach of a sunken and invisible wreck that would snatch the hull timbers from under her if she should strike it, and destroy a quarter of a million dollars' worth of steam-boat and cargo in five minutes, and maybe a hundred and fifty human lives into the bargain.