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.]

We will explore another of these great working-places—­this time, a group of mills as large as a modest village, yet devoted to one special product.  In 1864, Mr. Henry B. Seidel purchased a rolling-mill which had already been in operation with varied success for eighty years, and established the manufacture of large plates for iron ships and boilers.  In a few years, associating with himself his superintendent, Mr. Hastings, he greatly enlarged his operations, and the firm found their edifice too small.  An ample new one, one hundred and twenty-five feet long, was put up in 1870, upon the Church street side of their property, and with the introduction of all the new machines became capable of the quickest and completest operations.  Seidel & Hastings now run both mills, and turn out, when working night and day, at the rate of between five and six thousand tons of plate iron per annum.  They prepare their own “blooms” of charcoal iron at a great forge erected on their premises:  this forge has five fires, and is provided with the engines and blowing-cylinders for the manufacture of boiler iron, and the monster steam-hammers necessary in its preparation.  Nature’s products are here taught manners with a witness:  whatever shape they enter in, they leave in the form of pie-crust.  The tough old genius of iron, which has been trying since the creation to build itself into mountains or dissipate itself in bogs, is taught by the powerful persuasions of these gentlemen to pack and toughen itself into cards, and is only recognized by the foreman when he takes count of stock as “plate inch and a half” or “plate one-eighth.”