3. Another cause of TORNADOES independent of the monsoons is ingeniously explained by Dr. Franklin, when in the tropical countries a stratum of inferior air becomes so heated by its contact with the warm earth, that its expansion is increased more than is equivalent to the pressure of the stratum of air over it; or when the superior stratum becomes more condensed by cold than the inferior one by pressure, the upper region will descend and the lower one ascend. In this situation if one part of the atmosphere be hotter from some fortuitous circumstances, or, has less pressure over it, the lower stratum will begin to ascend at this part, and resemble water falling through a hole as mentioned above. If the lower region of air was going forwards with considerable velocity, it will gain an eddy by riling up this hole in the incumbent heavy air, so that the whirlpool or tornado has not only its progressive velocity, but its circular one also, which thus lifts up or overturns every thing within its spiral whirl. By the weaker whirlwinds in this country the trees are sometimes thrown down in a line of only twenty or forty yards in breadth, making a kind of avenue through a country. In the West Indies the sea rises like a cone in the whirl, and is met by black clouds produced by the cold upper air and the warm lower air being rapidly mixed; whence are produced the great and sudden rains called water-spouts; while the upper and lower airs exchange their plus or minus electricity in perpetual lightenings. LAND AND SEA-BREEZES. The sea being a transparent mass is less heated at its surface by the sun's rays than the land, and its continual change of surface contributes to preserve a greater uniformity in the heat of the air which hangs over it. Hence the surface of the tropical islands is more heated during the day than the sea that surrounds them, and cools more in the night by its greater elevation: whence in the afternoon when the lands of the tropical islands have been much heated by the sun, the air over them ascends pressed upwards by the cooler air of the incircling ocean, in the morning again the land becoming cooled more than the sea, the air over it descends by its increased gravity, and blows over the ocean near its shores. CONCLUSION. 1. There are various irregular winds besides those above described, which consist of horizontal or vertical eddies of air owing to the inequality of the earth's surface, or the juxtaposition of the sea. Other irregular winds have their origin from increased evaporation of water, or its sudden devaporation and descent in showers; others from the partial expansion and condensation of air by heat and cold; by the accumulation or defect of electric fluid, or to the air's new production or absorption occasioned by local causes not yet discovered. See Notes VII. and XXV.