ICE

is solid water, and is precipitated as snow, frost, or hail. It consists of colorle crystals of hexagonal form, with a well-marked habit of twinning. Ice at 0° C. is le dense than water, and floats on it. Ice contracts on melting. - Iceberg is a ma of ice floating in water, retaining its equilibrium by submersion of c. 87 per cent. of its bulk; frequently 300 ft. high; of great danger to ve els (e.g. Titanic); if in quantities, icebergs affect surrounding temp. considerably. Ice-floes are floating fields of ice driven together by pre ure of bergs. - Ice-breaker, a steamer specially. constructed for forcing a pa age through ice-bound waters; it may be used to clear a pa age for other ve els or simply for itself. The bow is shaped to mount and crush the ice downwards, and is very strong.