John Muir, climbing Mt. Ritter

"After scanning its face again and again, I began to scale it, picking my holds with intense caution. About halfway 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."