I do not think it should be objected to this doctrine that there are moist days attended with a brisk cold wind when no visible ice appears, and which are yet more disagreeable and destructive than frosty weather. For on these days the cold moisture, which is deposited on the skin is there evaporated and thus produces a degree of cold perhaps greater than the milder frosts. Whence even in such days both the disagreeable sensations and insalubrious effects belong to the cause abovementioned, viz. the intensity of the cold. Add to this that in these cold moist days as we pass along or as the wind blows upon us, a new sheet of cold water is as it were perpetually applied to us and hangs upon our bodies, now as water is 800 times denser than air and is a much better conductor of heat, we are starved with cold like those who go into a cold bath, both by the great number of particles in contact with the skin and their greater facility of receiving our heat. It may nevertheless be true that snows of long duration in our winters may be less injurious to vegetation than great rains and shorter frosts, for two reasons. 1. Because great rains carry down many thousand pounds worth of the best part of the manure off the lands into the sea, whereas snow dissolves more gradually and thence carries away less from the land; any one may distinguish a snow-flood from a rain-flood by the transparency of the water. Hence hills or fields with considerable inclination of surface should be ploughed horizontally that the furrows may stay the water from showers till it deposits its mud. 2. Snow protects vegetables from the severity of the frost, since it is always in a state of thaw where it is in contact with the earth; as the earth's heat is about 48 deg. and the heat of thawing snow is 32 deg. the vegetables between them are kept in a degree of heat about 40, by which many of them are preserved. See note on Muschus, Vol. II. of this work. NOTE XIII.--ELECTRICITY _Cold from each point cerulean lustres gleam._ CANTO I. l. 339. ELECTRIC POINTS.