পাতা:পদার্থবিদ্যাসার.djvu/৪৭

36 which has now become comparatively lighter than the land air, the land breeze is occasioned. Pup. What are the properties of the winds 2 Tut, They differ in different countries. In Bengal, the south wind is temperate, the north is cold, the east postilential, and the west hot and dry. - Pup. ffow are these properfies ov casioned? Tut. The south w nd is temperate, because it comes over the Indian Ocean ; the north wind is cold, because it comes from the frigid zone, or countries remote from the influence of the sun; the east is supposed to be pestilential, because it passes over jungly places: and the west is hot and dry, because it passes over much hot and dry land. Pup. Ilow are whirlwinds occasioned ? Tut. By the meeting of contrary currents of air in the salue point of the compass, and a sudden rarefaction of the air, &c. Tempests also arise from similar ᏟāᏓ8ᏚᏮᎦ. Pup. What are vapours and clouds? 'ut. Vapours are either thim, invisible, nroist particles, which float in the air; or being more condensed, and by that means rendered visible, are called clouds. * Pup. From whence do the vapours arise? Tut. They are exhaled by heat out of the earth, and by their lightness hang in the air. - Pup. Of what use are these vapours hanging in the air? . . . Tut. They cool the air when it is too hot; they afford us agreeable shade, when formed into clouds;