Chap. v. Violent Showers of Rain in different places vi. Storm of Salt Rain vii. Volcanic Showers, or Rain 1. General Remarks 2. Showers of Ashes in the Archipelago Page 155 157 161 ib. ib. 3. Shower of Dust that fell on a Ship near Iceland ib. 4. New kind of Rain 5. Surprising Shoal of Pumice-Stones found floating on the Sea xi. Avalanches, or falling Masses of detached and in cumbent Snow-heaps, from the Summits of lofty 162 165 166 ib. ib. 170 172 ib. 173 175 xii. General Nature of Hail 181 xiii. Violent Hail-Storms, accompanied with Stones of 182 XL. On Winds, or Atmospherical Currents 185 SECT. I. General Remarks on the Nature and Origin of Winds, Trade. Winds, Monsoons, Partial Winds, and Hur. ricanes ib. ii. Methodical Arrangement, Intensity, and Velocity vi. Occasional Winds; as Hurricanes, Tempests, Tor 5. General Remarks on Tornados, or Whirlwinds 248 251 XLI. On the Prester, or Water-Spout ii. Genuine Presters, or Water-Spouts iii. Means of preventing Mischief from Lightning XLVII. On Luminous and Burning Exhalations under the Names of Ignes Fatui; Will-o'-the- XLVIII. On Atmospheric Deceptions, Fata Morgana, Mirages, Glamer or Looming, Halos, Mul- tiplied Rainbows; Parhelions and Parasele- nites, or Mock-Suns, and Mock-Moons; ii. Fata Morgana; or Optical Appearances of Figures in the Sea and Air, in the Faro of Messina iii. Singular Instance of Atmospherical Refraction, by THE GALLERY OF NATURE AND ART PART I. NATURE. BOOK II. GEOLOGY. [CONTINUED.] CHAP. XXXIV. ATMOSPHERICAL DEPARTMENT. We now advance to the atmospherical phænomena of the science of Geology, in the extensive sense in which we have employed this term; and shall proceed to a brief survey of whatever is most curious or worthy of observation in the composition of the Atmosphere; the variation of Climate; the extremes of Heat and Cold; the existence of Electricity and electric Powers, as Thunder and Lightning, Aurora Borealis, Water-spouts; Falling-stars, and Ignes Fatui; Echoes, Wind, Hurricanes, and Storms; the origin of Mist, Dew, Sleet, Snow, Mirages, or Fata Morgana, Meteoric, Stones, and various other appearances connected with or dependent upon the preceding; and which collectively constitute the Science of Meteorology. VOL, IV. [2] CHAP. XXXV. GENERAL NATURE OF THE ATMOSPHERÉ. THE atmosphere is that invisible elastic fluid which surrounds the It was earth to an unknown height, and incloses it on all sides. thus denominated by the Greeks in consequence of the vavours which are continually mixing with it, or combined in it. In contemplating the nature of the atmosphere there are two points of considerable importance to be attended to, respecting which therefore we shall offer a summary of the best established facts and opinions of the present day; and these are the materials that enter into its composition, and the changes to which it is liable. SECTION 1. Composition of the Atmosphere. NEITHER the properties nor the composition of the atmosphere seems to have occupied much of the attention of the ancients. Aristotle considered it as one of the four elements, situated between the regions of water and fire, and mingled with two exhalations, the dry and moist; the first of which occasioned thunder, lightning, and wind; while the second produced rain, snow, and hail. The ancients, in general, seem to have considered the blue colours of the sky as essential to the atmosphere; and several of their philosophers believed that it was the constituent principle of other bodies, or at least that air and other bodies are mutually convertible into each other. Thus Lucretius: Semper enim quodcunque fluit de rebus, id omne From arμot, a vapour, and paipa, a sphere. Lib. v. 274. |