Rising at an equal height with the Connecticut, the Merrimack reaches the sea by a course only half as long, and hence has no leisure to form broad and fertile meadows, like the former, but is hurried along rapids, and down numerous falls, without long delay.  The banks are generally steep and high, with a narrow interval reaching back to the hills, which is only rarely or partially overflown at present, and is much valued by the farmers.  Between Chelmsford and Concord, in New Hampshire, it varies from twenty to seventy-five rods in width.  It is probably wider than it was formerly, in many places, owing to the trees having been cut down, and the consequent wasting away of its banks.  The influence of the Pawtucket Dam is felt as far up as Cromwell’s Falls, and many think that the banks are being abraded and the river filled up again by this cause.  Like all our rivers, it is liable to freshets, and the Pemigewasset has been known to rise twenty-five feet in a few hours.  It is navigable for vessels of burden about twenty miles; for canal-boats, by means of locks, as far as Concord in New Hampshire, about seventy-five miles from its mouth; and for smaller boats to Plymouth, one hundred and thirteen miles.  A small steamboat once plied between Lowell and Nashua, before the railroad was built, and one now runs from Newburyport to Haverhill.

Unfitted to some extent for the purposes of commerce by the sand-bar at its mouth, see how this river was devoted from the first to the service of manufactures.  Issuing from the iron region of Franconia, and flowing through still uncut forests, by inexhaustible ledges of granite, with Squam, and Winnipiseogee, and Newfound, and Massabesic Lakes for its mill-ponds, it falls over a succession of natural dams, where it has been offering its privileges in vain for ages, until at last the Yankee race came to improve them.  Standing at its mouth, look up its sparkling stream to its source,—­a silver cascade which falls all the way from the White Mountains to the sea,—­and behold a city on each successive plateau, a busy colony of human beaver around every fall.  Not to mention Newburyport and Haverhill, see Lawrence, and Lowell, and Nashua, and Manchester, and Concord, gleaming one above the other.  When at length it has escaped from under the last of the factories, it has a level and unmolested passage to the sea, a mere waste water, as it were, bearing little with it but its fame; its pleasant course revealed by the morning fog which hangs over it, and the sails of the few small vessels which transact the commerce of Haverhill and Newburyport.  But its real vessels are railroad cars, and its true and main stream, flowing by an iron channel farther south, may be traced by a long line of vapor amid the hills, which no morning wind ever disperses, to where it empties into the sea at Boston.  This side is the louder murmur now.  Instead of the scream of a fish-hawk scaring the fishes, is heard the whistle of the steam-engine, arousing a country to its progress.