downward from a height of fifty feet, along the arc of a circle with such a radius, soaring to an equal altitude, pausing for one breathless instant, then sweeping dizzily backward—no one who has not tried it can conceive the terrors of such sport to the novice. Thurston came out of his tent one day and asked for instruction in the mystery of propelling the swing—the art of rising and sitting, which every boy has mastered. In a few moments he had acquired the trick and was swinging higher than the most experienced of us had dared. We shuddered to look at his fearful flights.
"St-t-top him," said the quartermaster, snailing lazily along from the mess-tent, where he had been lunching; "h—e d-doesn't know that if h—e g-g-goes c-clear over h—e'll w—ind up the sw—ing."
With such energy was that strong man cannonading himself through the air that at each extremity of his increasing arc his body, standing in the swing, was almost horizontal. Should he once pass above the level of the rope's attachment he would be lost; the rope would slacken and he would fall vertically to a point as far below as he had gone above, and then the sudden tension of the rope would
