FROST, such a state of the atmosphere as causes the congelation or freezing of water or other fluids into ice. In the more northern parts of the world, even solid bodies are affected by frost, though this is only or chiefly in consequence of the moisture they contain, which being frozen into ice, and so expanding as water is known to do when frozen, it bursts, and rends any thing in which it is contained, as plants, trees, stones, and large rocks. Many fluids expand by frost, as water, which expands about one-tenth part, for which reason ice floats in water ; but others again contract, as quicksilver, and thence frozen quicksilver sinks in the fluid metal.
Frost, being derived from the atmos phere, naturally proceeds from the upper parts of bodies downwards, as the water and the earth : so, the longer a frost is continued, the thicker the ice becomes upon the water in ponds, and the deeper into the earth the ground is frozen. In about 16 or 17 days frost, Mr. Boyle found it had penetrated 14 inches into the ground. At Moscow, in a hard season, the frost will penetrate twofeet deep into 1. , the ground : and Captain James found it , penetrated 10 feet deep in Charlton L Island, and the water in the same island - was frozen to the depth of six feet. Shef fer assures us, that in Sweden the frost pierces two cubits, or Swedish ells, into the earth, and turns what moisture is found there into a whitish substance, like ice ; and standing water to three ells or more. The same author also mentions sudden cracks or rifts in the ice of the lakes of Sweden, nine or ten feet deep, and many leagues long ; the rupture being made with a noise not less loud than if many guns were discharged together. By such means, however, the fishes are nished with air ; so that they are rarely found dead.
The natural history of frosts furnish ve ry extraordinary effects. The trees are often scorched and burnt up, as with the most excessive heat, in consequence of the separation of water from the air, which is therefore very drying In the great frost in 1683, the trunks of oak, ash, walnut, &c. were miserably split and cleft, so that they might be seen through, and the cracks often attended with dreadful noises like the explosion offire-arms. Phi los. Trans.'Number 165.
The close of the year 1708, and the be ginning of 1709, were remarkable, throughout the greatest part of Europe, for a severe frost. Dr. Derham says it was the greatest in degree, if not the most universal, in the memory of man ; ex tending through most parts of Europe, though scarcely felt in Scotland or Ire land.
In very cold countries, meat may be preserved by the frost six or seven months, and prove tolerably good eating. See Captain Middleton's observations made in Hudson's Bay, in the Philos. Trans. Number 465, sect. 2.
In that climate the frost seems never out of the ground, it having been found hard frozen in the two summer months. Brandy and spirit, set out in the open air. freeze to solid ice in three or four hours.
Lakes and standing waters, not above 10 or 12 feet deep, are frozen to the ground in winter, and all their fish perish. But in rivers, where the current of the tide is strong, the ice does not reach so deep, and the fish are preserved. Id. ib.
Some remarkable instances of frost in Europe, and chiefly in England, are re corded as below ; in the year 220 Frost in Britain that lasted five months.
250 The Thames frozen nine weeks. 291 Most rivers in Britain frozen six weeks.
359 Severe frost in Scotland for 14 weeks.
508 The rivers in Britain frozen for two months.
558 The Danube quite frozen over. 695 Thames frozen six weeks; booths built on it.
759 Frost from Oct. 1, till Feb. 26,, 760.
S27 Frost in England for nine weeks. 859 Carriages used on the Adriatic Sea.
908 Most rivers in England frozen two months.
923 The Thames frozen 13 weeks. 987 Frost lasted 120 days : began De cember 22.
998 The Thames frozen five weeks. 1035 Severe frost on June 24: the corn and fruits destroyed.
1063 The Thames frozen fourteen weeks.
1076 Frost in England from November till April.
1114 Several wooden bridges carried away by ice.
1205 Frost in England from January 14, till March 22.
1407 Frost that lasted 15 weeks.
1434 From Novem. 24, till Feb. 10, Thames frozen down to Graves end.
1683 Frost for thirteen weeks.
1708-9 Severe frost for many weeks. 1715 The same for many weeks.
1739 One for nine weeks : began De cember 24.
1742 Severe frost for many weeks. 1747 Severe frost in Russia.
1751 Severe one in England.
1760 The same in Germany.
1776 The same in England.
1788 The Thames frozen below bridge ; booths on it.
1794 Hard frost of many weeks. Ther. at London, mostly at 20 below 0 of Fahrenheit.
Hoar frost, is the dew frozen or con gealed early in cold mornings; chiefly in autumn. Though many Cartesians will have it formed of a cloud ; and either congealed in the cloud, and so let fall, or ready to be congealed as soon as it ar rives at the earth.
Hoar frost, M. Regius observes, con sists of an assemblage of little parcels of ice crystals, which are of various figures, according to the different disposition of the vapours, when met and condensed by the cold.