month of the year, and that it blows longest in July and Angust; that the north-east blows most constantly during January, March, April, May, and June, and most seldom during February, July, September, and December; and that the north-west wind blows oftener from November to March, and more seldom during September and October than any other mouths. The south-west winds are also most frequent at Bristol, and next to them are the north east *. The following Table of the winds at Lancaster has been drawn up from a register kept for seven years at that place †. The following Table is an abstract of nine years observations made at Dumfries by Mr. Copland .. The following Table is an abstract of seven years observations made by Dr. Meek at Cambuslang near Glasgow §. It appears from the register from which this Table was extracted that the north-east wind blows much more frequently in April, May, and June, and the south-west in July, August, and September, than at any other period. The south-west is by far the most fre. Phil. Trans. Ixvi. 2. + Manchester Trans. iv. 234. VOL. IV. Ibid. Statistical Account of Scotland, v. 245. At quent wind all over Scotland, especially on the west coast. Saltcoats in Ayrshire, for instance, it blows three-fourths of the year; and along the whole coast of Murray, on the north-east side of Scotland, it blows for two-thirds of the year. East winds are common all over Great Britain during April and May; but their in. fluence is felt most severely on the eastern coast. The following Table exhibits a view of the number of days during which the westerly and easterly winds blow in a year at different parts of the island. Under the term westerly are included the north-west, west, south-west, and south; the term easterly is taken in the same latitude. In Ireland the south-west and west are the grand trade-winds, blowing most in summer, autumn, and winter, and least in spring. The north-east blows most in spring, and nearly double to what it does in autumn and winter. The south-east and north-west are nearly equal, and are most frequent after the south-west and west §. At Copenhagen the prevailing winds are the east and south-east ; at Stockholm, the west and north |. In Russia, from an average of a register of sixteen years, the winds blow from November to April in the following order: W. N.W. E. S.W. S. Days 45 N.E. N. S.E. 23 22 20 19 14 12 + Edin. Trans. i. 203. Ibid. * Manchester Trans. iv. Rutty's Hist. of the Weather, &c. in Dublin. And during the other six months, W. Days 27 N.W. 27 E. 19 S.W. S. N.E. N. S.E. 24 22 15 32 18 The west wind blows during the whole year 72 days; the northwest 53; the south-west and north 56 days each. During summer it is calm for 41 days, and during winter for 21*. In Norway the most frequent winds are the south, the south-west, and south-east. The wind at Bergen is seldom directly west, but ge nerally south-west or south-east; a north-west, and especially a north-east wind, are but little known there+. From the whole of these facts, it appears that the most frequent winds on the south coasts of Europe are the north, the north-east, and north-west; and on the western coast, the south-west: that in the interior parts which lie most contiguous to the Atlantic ocean, south-west winds are also most frequent; but that easterly winds prevail in Germany. Westerly winds are also most frequent on the north-east coast of Asia. It is probable that the winds are most constant in the south tem. perate zone, which is in a great measure covered with water, than in the north temperate zone, where their direction must be frequently interrupted and altered by mountains and other causes. M. de la Caille, who was sent thither by the French king to make astronomical observations, informs us, that at the Cape of Good Hope the main winds are the south-east and north-west; that other wiuds seldom last longer than a few hours; and that the east and north-east winds blow very seldom. The south-east wind blows in most months of the year, but chiefly from October to April; the north-west prevails during the other six months, bringing along with it rain, and tempests, and hurricanes. Between the Cape of Good Hope and New Holland the winds are commonly westerly, and blow in the following order: north-west, south-west, west, north +. In the Great South Sea, from latitude 30° to 40° south, the south-east trade-wind blows most frequently, especially when the sun approaches the tropic of Capricorn; the wind next to it in frequency is the north-west, and next to that is the south-west. Guthrie on the Climate of Russia, Edin. Trans. ii. + Pontoppidan's Nat. Hist, of Norway, part. i. Meteorological Tables at the end of Philip's and White's Voyages. From south latitude 40° to 50° the prevailing wind is the northwest, and next the south-west. From 50° to 60° the most frequent wind is also the north-west, and next to it is the west *. Thus it appears that the trade-winds sometimes extend farther into the south temperate zone than their usual limits, particularly during summer; that beyond their influence the winds are commonly westerly; and that they blow in the following order: northwest, south-west, west. Such is the present state of the history of the direction of the winds. In the torrid zone they blow constantly from the northeast on the north side of the equator, and from the south-east on the south side of it. In the north temperate zone they blow most frequently from the south-west; in the south temperate zone from the north-west, changing, however, frequently to all points of the compass; and in the north temperate zone blowing, particularly during the spring, from the north-east. As to the velocity of the wind, its variations are almost infinite, from the gentlest breeze to the hurricane which tears up trees and blows down houses. It has been remarked, that our most violent winds take place when neither the heat nor the cold is greatest; that violent winds generally extend over a great tract of country; and that they are accompanied by sudden and great falls in the mer. cury of the barometer. The wind is sometimes very violent at a distance from the earth, while it is quite calm at its surface. one occasion Lunardi went at the rate of seventy miles an hour in his balloon, though it was quite calm at Edinburgh when he ascended, and continued so during his whole voyage. The following Table, drawn up by Mr. Smeaton, will give the reader a pretty precise idea of the velocity of the wind in different circumstances t. * Wale's Meteor. Tables. + Phil. Trans. 1759, p. 165. On Miles per Hour. Feet per Perpendicular Force on one square Foot, in Second. Averdupois Pounds and Parts. Let us now consider the cause of these numerous currents in the atmosphere. It cannot be doubted that the surface of the earth under the torrid zone is much more heated by the rays of the sun than under the frozen or temperate zones; because the rays fall upon it much more perpendicularly. This heat is communicated to the air near the surface of the torrid zone, which being thereby rarefied, ascends; and its place is supplied by colder air, which rushes in from the north and south. Now the diurnal motion of the earth is greatest at the equator, and diminishes gradually as we approach the poles, where it ceases altogether. Every spot of the earth's surface at the equator moves at the rate of fifteen geographical miles in a minute; at the 40° of latitude, it moves at about eleven miles and a half in a minute; and at the 30°, at nearly thirteen miles. The atmosphere, by moving continually round along with the earth, has acquired the same degree of motion; so that those parts of it which are above the equator move faster than those which are at a distance. Were a portion of the atmosphere to be transported in an instant from latitude 30° to the equator, it would not immediately acquire the |