SNOW

, a well known meteor, formed by the freezing of the vapours in the atmosphere. It differs from hail and hoar-frost in being as it were crystallized, which they are not. This appears on examination of a flake of Snow by a magnifying glass; when the whole of it appears to be composed of fine shining spicula diverging like rays from a centre. As the flakes descend | through the atmosphere, they are continually joined by more of these radiated spicula, and thus increase in bulk like the drops of rain or hailstones; so that it seems as if the whole body of Snow were an infinite mass of icicles irregularly figured.

The lightness os Snow, although it is firm ice, is owing to the excess of its surface, in comparison to the matter contained under it; as even gold itself may be extended in surface, till it will float upon the least breath of air.

According to Beccaria, clouds of Snow differ in nothing from clouds of rain, but in the circumstance of cold that freezes them. Both the regular diffusion of the Snow, and the regularity of the structure of its parts, shew that clouds of Snow are acted upon by some uniform cause like electricity; and he endeavours to shew how electricity is capable of forming these figures. He was confirmed in his conjectures by observing, that his apparatus for shewing the electricity of the atmosphere, never failed to be electrified by Snow as well as by rain. Professor Wintrop sometimes found his apparatus electrified by Snow when driven about by the wind, though it had not been affected by it when the Snow itself was falling. A more intense electricity, according to Beccaria, unites the particles of hail more closely than the more moderate electricity does those of Snow, in the same manner as we see that the drops of rain which fall from the thunder-clouds, are larger than those which fall from others, though the former descend through a less space.

In the northern countries, the ground is covered with snow for several months; which proves exceedingly favourable for vegetation, by preserving the plants from those intense frosts which are common in such countries, and which would certainly destroy them. Bartholin ascribes great virtues to Snow-water, but experience does not seem to warrant his assertions. Snowwater, or ice-water, is always deprived of its fixed air: and those nations who live among the Alps, and use it for their constant drink, are subject to affections of the throat, which it is thought are occasioned by it.

From some late experiments on the quantity of water yielded by Snow, it appears that the latter gives only about one-tenth of its bulk in water.