Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2- Appendix): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

64 FIGURES USED TO Calm. 1 Light Air 2 Light Breeze 3 Gentle Breeze 4 Moderate Breeze . 5 Fresh Breeze , DENOTE THE FORCE OF THE WIND. Or just sufficient to give steerage way. Or that in which a man- of war, with all sail set, and clean full, would go in smooth water from 6 Strong Breeze . 7 Moderate Gale 8 Fresh Gale 9 Strong Gale 10 Whole Gale Or that to which a well- conditioned man-of- war could just carry- in chase, full and by 1 to 2 knots. 3 to 4 knots. 5 to 6 knots. Royals, &c. Single-reefed topsails and top-gall, sails. Double-reefed topsails, jib, &c. Treble-reefed topsails, &c. Close-reefed topsails and courses. 11 Storm 12 Hurricane .Or that with which she could scarcely bear close-reefed main-topsail and reefed fore-sail. .Or that which would reduce her to storm stay-sails. . Or that which no canvass could withstand. LETTERS DENOTING THE STATE OF THE WEATHER. b Blue sky; (whether clear, or hazy atmosphere). c Clouds ; (detached passing clouds). d Drizzling rain. f Foggy f Thick fog. g Gloomy (dark weather). h Hail. 1 Lightning. m Misty (hazy atmosphere). o Overcast (or the whole sky covered with thick clouds). p Passing (temporary showers), q Squally. r Rain (continued rain), s Snow. t Thunder. u Ugly (threatening appearances). V Visible (clear atmosphere). w Wet dew. . Under any letter, indicates an extraordinary degree. By the combination of these letters, all theordinary phenomena of the weather may be expressed with facility and brevity. Examples :—Bcm, Blue sky, with passing clouds, and a hazy atmosphere. Gv, Gloomy dark weather, but distant objects remarkably visible. Qpdlt, Very hard squalls, with passing showers of drizzle, and accompanied by lightning with very heavy thunder.