For I dipt into the future, far as human eye could see, Saw the vision of the world, and all the wonder that would be; Saw the heavens fill with commerce, Argosies of magic sails, Pilots of the purple twilight, dropping down with costly bales; Heard the heavens fill with shouting, and there rain'd a ghastly dew, From the nations' airy navies grappling in the central blue.