“Such are the limitations of the common mind, and so thoroughly engrossing are the cares of common life, that only the few among men can discern through the glitter and dazzle of present prosperity the dark outlines of approaching disasters, even though they may have come up to our very gates, and are already within striking distance. The yawning seam and corroded bolt conceal their defects from the mariner until the storm calls all hands to the pumps.”