“Rivers are as various in their forms as forest trees.  The Mississippi is like an oak with enormous branches.  What a branch is the Red River, the Arkansas, the Ohio, the Missouri!  The Hudson is like the pine or poplar—­mainly trunk.  From New York to Albany there is only an inconsiderable limb or two, and but few gnarls and excrescences.  Cut off the Rondout, the Esopus, the Catskill and two or three similar tributaries on the east side, and only some twigs remain.  There are some crooked places, it is true, but, on the whole, the Hudson presents a fine, symmetrical shaft that would be hard to match in any river in the world.  Among our own water-courses it stands preeminent.  The Columbia—­called by Major Winthrop the Achilles of rivers—­is a more haughty and impetuous stream; the Mississippi is, of course, vastly larger and longer; the St. Lawrence would carry the Hudson as a trophy in his belt and hardly know the difference; yet our river is doubtless the most beautiful of them all.  It pleases like a mountain lake.  It has all the sweetness and placidity that go with such bodies of water, on the one hand, and all their bold and rugged scenery on the other.  In summer, a passage up or down its course in one of the day steamers is as near an idyl of travel as can be had, perhaps, anywhere in the world.  Then its permanent and uniform volume, its fullness and equipoise at all seasons, and its gently-flowing currents give it further the character of a lake, or of the sea itself.  Of the Hudson it may be said that it is a very large river for its size,—­that is for the quantity of water it discharges into the sea.  Its watershed is comparatively small—­less, I think, than that of the Connecticut.  It is a huge trough with a very slight incline, through which the current moves very slowly, and which would fill from the sea were its supplies from the mountains cut off.  Its fall from Albany to the bay is only about five feet.  Any object upon it, drifting with the current, progresses southward no more than eight miles in twenty-four hours.  The ebb-tide will carry it about twelve miles and the flood set it back from seven to nine.  A drop of water at Albany, therefore, will be nearly three weeks in reaching New York, though it will get pretty well pickled some days earlier.  Some rivers by their volume and impetuosity penetrate the sea, but here the sea is the aggressor, and sometimes meets the mountain water nearly half way.  This fact was illustrated a couple of years ago, when the basin of the Hudson was visited by one of the most severe droughts ever known in this part of the State.  In the early winter after the river was frozen over above Poughkeepsie, it was discovered that immense numbers of fish were retreating up stream before the slow encroachment of salt water.  There was a general exodus of the finny tribes from the whole lower part of the river; it was like the spring and fall migration of the birds, or the fleeing of the population