Standing by Harrington’s pond-hole in the swamp, which had skimmed over, we saw that there were many holes through the thin black ice, of various sizes, from a few inches to more than a foot in diameter, all of which were perfectly circular. Mr. H. asked me if I could account for it. As we stood considering, we jarred the boggy ground and made a dimple in the water, and this accident, we thought, betrayed the cause of it: i. e. the circular wavelets so wore off the edges of the ice when once a hole was made.