Such are the bare commercial facts. But stand in one of these noisy working-grounds of a manufacturing place like Wilmington, or ride up to the top of one of their buildings on the steam-elevators which some of them employ. Think how these men of iron are changing the surface of the earth, spiking rails to the prairie in distant territories, or sending into Polynesian archipelagoes the rivet on whose integrity depends the safety of the iron ship. How needful to human progress is the conscientious perfection of their work! What tact they must employ in dealing with phalanxes of laborers of different nations and imperfect intelligence! What a stimulus to genius they are, with their readiness to catch at any labor-saving machine! See that astute-looking dwarf of an apparatus, biting off red-hot ends of rods, closing its jaws together upon them in such a way as to form a four-square mould, then smartly hitting one end so as to make a projecting head: a railroad spike is turned off in a moment. See this other making "nuts" as smartly as a baker makes ginger-nuts: some are raw and some are cooked--that is, some are punched hot and some cold, sufficing for different purposes: the cold are the softer, and the easier to "tap" or perforate with the screw--thread. Other machines are scissors trimming plates of iron like cardboard; others, in a careless kind of way, spend all their time in nipping off whatever bolts and bars are presented to them; and others make pretty rows of rivet-holes all along the edges of huge iron plates. These animated creatures of the mill, performing their tasks like child's play, are efforts of intellectual genius as truly as are the dramas of Shakespeare. And busy talents are growing up in our manufacturing centres as in hotbeds, each one trying to carry the domain of mechanical substitution a little farther, and so escape the necessity, so costly in America, of paying for man-power. In several ways a grand manufactory is a college, stimulating the human minds engaged there in the highest degree, setting a premium on intellect and culture, and reminding us that whoever caused some idea to take shape that never had an existence before, was called by the ancients a "_poeta_." [Illustration: STEAM MANUFACTORY OF SUPERPHOSPHATES.]