elevator is an amphibious institution, and flourishes only on the banks of navigable waters.  When its head is ensconced within its box, and the beast of prey is thus nearly hidden within the building, the unsuspicious vessel is brought up within reach of the creature’s trunk, and down it comes, like a musquito’s proboscis, right through the deck, in at the open aperture of the hole, and so into the very vitals and bowels of the ship.  When there, it goes to work upon its food with a greed and an avidity that is disgusting to a beholder of any taste or imagination.  And now I must explain the anatomical arrangement by which the elevator still devours and continues to devour, till the corn within its reach has all been swallowed, masticated, and digested.  Its long trunk, as seen slanting down from out of the building across the wharf and into the ship, is a mere wooden pipe; but this pipe is divided within.  It has two departments; and as the grain-bearing troughs pass up the one on a pliable band, they pass empty down the other.  The system, therefore, is that of an ordinary dredging machine only that corn and not mud is taken away, and that the buckets or troughs are hidden from sight.  Below, within the stomach of the poor bark, three or four laborers are at work, helping to feed the elevator.  They shovel the corn up toward its maw, so that at every swallow he should take in all that he can hold.  Thus the troughs, as they ascend, are kept full, and when they reach the upper building they empty themselves into a shoot, over which a porter stands guard, moderating the shoot by a door, which the weight of his finger can open and close.  Through this doorway the corn runs into a measure, and is weighed.  By measures of forty bushels each, the tale is kept.  There stands the apparatus, with the figures plainly marked, over against the porter’s eye; and as the sum mounts nearly up to forty bushels he closes the door till the grains run thinly through, hardly a handful at a time, so that the balance is exactly struck.  Then the teller standing by marks down his figure, and the record is made.  The exact porter touches the string of another door, and the forty bushels of corn run out at the bottom of the measure, disappear down another shoot, slanting also toward the water, and deposit themselves in the canal boat.  The transit of the bushels of corn from the larger vessel to the smaller will have taken less than a minute, and the cost of that transit will have been—­a farthing.

But I have spoken of the rivers of wheat, and I must explain what are those rivers.  In the working of the elevator, which I have just attempted to describe, the two vessels were supposed to be lying at the same wharf on the same side of the building, in the same water, the smaller vessel inside the larger one.  When this is the case the corn runs direct from the weighing measure into the shoot that communicates with the canal boat.  But there is not room or