Thoreau writes in his journal on 18 August:
I sailed on the North River last night with my flute, and my music was a tinkling stream which meandered with the river, and fell from note to note as a brook from rock to rock. I did not hear the strains after they had issued from the flute, but before they were breathed into it, for the original strain precedes the sound by as much as the echo follows after, and the rest is the perquisite of the rocks and trees and beasts. Unpremeditated music is the true gauge which measures the current of our thoughts, the very undertow of our life’s stream.
