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See also:HAIL (O. Eng. kcegl and hagol, 1 cf. the cognate See also:Teutonic hagel, as in See also:German, Dutch, See also:Swedish, &c.; the Gr. K&XX17E, pebble, is probably allied) , the name for rounded masses or single pellets of See also:ice falling from the clouds in a shower . True See also:hail has a See also:con-centric structure caused by the frozen particles of moisture first descending into a warm See also:cloud, whence they are carried upwards on an ascending current of heated See also:air into a See also:cold stratum where the fresh coating of See also:water vapour deposited in the cloud is frozen . The hailstone descends again, receives a fresh coating, is carried up once more, refrozen, and again descends . Thus the hailstone grows until the current is no longer strong enough to support it when it falls to the ground . At times masses of hail are frozen together, and a very sudden cooling will sometimes result in the formation of ragged masses of ice that fall with disastrous results . Hail must be distinguished from the frozen See also:snow, " soft-hail " or " graupel," that often falls at the See also:rear of a See also:spring See also:cyclone, since true hail is almost entirely a summer phenomenon, and falls most frequently in thunderstorms which are produced under the conditions that are favourable to the formation of hail, i.e. See also:great See also:heat, a still See also:atmosphere, the See also:production of strong See also:local convection currents in consequence, and the passage of a cold upper See also:drift . |
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[next] LORD DAVID DALRYMPLE HAILES (1726-1792) |
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