Rivers await their due celebration.  We easily see that Nile, Ganges, Euphrates, Jordan, Tiber, Thames, are rivers of influence in human history, no less than water-currents on the earth’s surface.  They have borne barks and barges that the eye never saw.  They have brought on their soft bosoms freight to the cities of the brain, as well as to Memphis, Rome, London.  Some experience of their spiritual influence must have fallen to the lot of most men.  The loved and lovely Merrimac no longer accedes to the writer’s eye, but, as of old, glides securely seaward in his thought,—­like a strain of masterly music long ago heard, and, when heard, identical in its suggestions with the total significance and vital progress of one’s experience, that, intertwining itself as a twin thread with the shuttled fibre of life, it was woven into the same fabric, and became an inseparable part of the consciousness; so, hearken when one will, after the changes and accessions of many peopled years, and amid the thousand-footed trample of the mob of immediate impressions, still secure and predominant it is heard subtly sounding.  Deep conversation with any river readily interprets to us that venerable mythus which connects Eden with the four rivers of the world; as if water must flow where man is chiefly blest.

But the point here to be emphasized is, that rivers are the progressive and public element in its geographical expression.  They throw the continent open; they are doors and windows, through which the nations look forth upon the world, and leave and enter their own household.  They are the hospitality of the continent,—­every river-mouth chanting out over the sea a perpetual, “Walk in,” to all the world.  Or again, they are geographical senses,—­eyes, ears, and speech; for of these supreme mediators in the body, voice, vision, and hearing, it is the office, as of rivers, to open communication between the interior and exterior world; they are rivers of access to the outlying universe of men and things, which enters them, and approaches the soul through the freighted suggestions of sight and sound.  Rivers, lastly, are the geographical symbol of public spirit, the flowing and connecting element, suggesting common interests and large systems of action.

Thus in these characteristics of Various Productiveness, Unity, and Openness or Publicity, the continent indicates the description of man who may be its fit habitant.  It suggests a nation vast in numbers and in power, existing not as an aggregate of fragments, but as an organic unit, the vital spirit of the whole prevailing in each of its parts; and consequently predicts a man suitable for wide and yet intimate societies.  Let us not, however, thoughtlessly jump to accept these easy prognostics; first let it be fully understood what an enormous demand they imply.  Americans speak complacently of their prospective one hundred millions of inhabitants; but do they bear well in mind that the requisition upon the individual is augmented