1396. Ice is water in the solid state, during which the temperature remains constant, being 32ﾦ of the scale of Fahrenheit. Ice is considerably lighter than water, namely, about one eighth part; and this increase of dimensions is acquired with prodigious force, sufficient to burst the strongest iron vessels, and even pieces of artillery. Congelation takes place much more suddenly than the opposite process of liquefaction; and, of course, the same quantity of heat must be more rapidly extricated in freezing than it is absorbed in thawing; the heat thus extricated being disposed to fly off in all directions, and little of it being retained by the neighbouring bodies, more heat is lost than is gained by the alternation: so that where ice has once been formed, its production is in this manner redoubled.
