John Muir on Mt. Ritter:
After scanning its face again and again,
I began to scale it, picking my holds
With intense caution. About half-way
To the top, I was suddenly brought to
A dead stop, with arms outspread
Clinging close to the face of the rock
Unable to move hand or foot
Either up or down. My doom
Appeared fixed. I MUST fall.
There would be a moment of 
Bewilderment, and then,
A lifeless rumble down the cliff
To the glacier below.
My mind seemed to fill with a 
Stifling smoke. This terrible eclipse
Lasted only a moment, when life blazed
Forth again with preternatural clearness.
I seemed suddenly to become possessed
Of a new sense. My trembling muscles
Became firm again, every rift and flaw in
The rock was seen as through a microscope,
My limbs moved with a positiveness and precision
With which I seemed to have
Nothing at all to do.

                         Gary Snyder