"Earth's children cleave to Earth"

Earth's children cleave to Earth--her frail
  Decaying children dread decay.
Yon wreath of mist that leaves the vale,
  And lessens in the morning ray:
Look, how, by mountain rivulet,
  It lingers as it upward creeps,
And clings to fern and copsewood set
  Along the green and dewy steeps:
Clings to the fragrant kalmia, clings
  To precipices fringed with grass,
Dark maples where the wood-thrush sings,
  And bowers of fragrant sassafras.
Yet all in vain--it passes still
  From hold to hold, it cannot stay,
And in the very beams that fill
  The world with glory, wastes away,
Till, parting from the mountain's brow,
  It vanishes from human eye,
And that which sprung of earth is now
  A portion of the glorious sky.