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beneath. I sometimes used to cast on stones to try the 
strength of the ice, and those which broke through car¬ 
ried in air with them, which formed very large and con¬ 
spicuous white bubbles beneath. One day when I came 
* to the same place forty-eight hours afterward, I found 
that those large bubbles were still perfect, though an inch 
more of ice had formed, as I could see distinctly by the 
seam in the edge of a cake. But as the last two days 
had been very warm, like an Indian summer, the ice 
was not now transparent, showing the dark green color 
of the water, and the bottom, but opaque and whitish or 
gray, and though twice as thick was hardly stronger 
than before, for the air bubbles had greatly expanded 
under this heat and run together, and lost their regular¬ 
ity ; they were no longer one directly over another, but 
often like silvery coins poured from a bag, one overlap¬ 
ping another, or in thin flakes, as if occupying slight 
cleavages. The beauty of the ice was gone, and it was 
too late to study the bottom. Being curious to know 
what position my great bubbles occupied with regard to 
the new ice, I broke out a cake containing a middling 
sized one, and turned it bottom upward. The new ice 
had formed around and under the bubble, so that it was 
included between the two ices. It was wholly in the 
lower ice, but close against the upper, and was flattish, 
or perhaps slightly lenticular, with a rounded edge, a 
quarter of an inch deep by four inches in diameter; and 
I was surprised to find that directly under the bubble the 
ice was melted with great regularity in the form of a sau¬ 
cer reversed, to the height of five eighths of an inch in 
the middle, leaving a thin partition there between the 
water and the bubble, hardly an eighth of an inch thick ; 
and in many places the small bubbles in this partition had 
