с V D FORMULA FOR RECORDING STATE OF THE WEATHER. B denotes Blue Sky, i.e. clear or u denotes Ugly, with a heavy hazy atmosphere. appearance of the Cloudy detached weather. opening clouds. Visibility of distant Drizzling Rain. objects. F Fog-FF Thick Fog. W Wet dew. ordinary degree. By the combination of these M Misty or Hazy-so as letters all the ordinary pheno- opening clouds, but hazy round Squally. the horizon. Rain-continuous rain. Gv-Gloomy dark weather, but Snow. distant objects remarkably Thunder. visible. G P Q S T USE OF INSTRUMENTS IN FORETELLING WEATHER. On Barometer Scales the fol- And the following summary lowing contractions may be use- may be useful generally :ful in North Latitude :RISE FALL RISE FALL FOR S. Wly. Cold, Dry, Warm, Wet, Less More Wind. Except Wet Except Wet Except Wet from from from from N.Eward. N.Eward. Cold Side. Cold Side. In other Latitudes substitute South or Southward for North, &c. or or Much inequality of atmospheric pressure or temperature, great depression or elevation of the barometer, sudden or rapid alternations, great falls of rain or snow-indicate more or less change, more or less wind, with its usual accompaniments, either in some places only, or throughout an extensive area of hundreds of miles, if not thousands. Speaking generally, there is far less occasion to give warning of southerly storms by signal than of northerly, because those from the southward are preceded by notable signs in the atmosphere, by a falling barometer, and by a temperature higher than usual to the season ; whereas, on the contrary, dangerous storms from a polar quarter (N. W. to N. E.) are sometimes sudden, and usually are preceded by a rising barometer, which is often misleading, especially when accompanied by a temporary lull, of perhaps a day or two, with an appearance of fine weather. THERMOMETER. Fahrenheit, Réaumur, and the Centigrade Scales. CNT. Fahr. RMR. CNT. Fahr. Rur. CNT. Fahr. Rmr. Cnt. Fahr. Rmr. 48 13'6 23 448 26 53-6 22'4 40*8 518 256 46-4 446 428 41 392 374 356 338 34'6 336 Zero 32 100 140 20 20 4 16 99 2102 79'2 59 138'2 47*2 19 66'2 508 1608 98 208'4784 58 | 136'4 | 46 4 18 644 144 22 7617-6 97 57 134*6 45'6 17 62'6 9'4 184 96 204'8 76-8 · 56 1328 16 60*8 128 24 II2 1982 95 203 76 55 131 44 15 59 12 25 13 20 94 2012 752 43'2 14 1408 20*8 93 1994 744 53 1274 42'4 13 55'4 10'4 27 16'6 21.6 92 197'6 736 52 12566 416 12 9'6 28 184 91 1958 72-8 51 1238 II 8.8 232 90 194 72 50 122 40 50 8 30 22 89 | 1922 24 712 49 120*2 39'2 48'2 8S 72 31 23.8 243 190'4 70*4 48 32 87 1886 696 256 47 1166 37-6 86 33 186*8 688 274 26-4 46 114'8 368 6 34 29'2 27'2 85 185 68 45 113 36 5 4 84 1832 67'2 35 31 28 IN1'2 352 4 32 36 328 28.8 83 1814 664 43 1094 34-4 24 37 82 179*6 65'6 29-6 42 107-6 2 16 38 36-4 81 304 1778 648 41 105*8 32-8 1 o'8 39 38*2 31'2 80 176 64 40 104 32 Zero 40 79 174'2 63'2 39 1022 31'2 41 78 172'4 6294 38 1004 30'4 2 16 42 77 1706 616 37 24 43 76 168360-8 45'4 34'4 968 288 4 248 3'2 44 47'2 35'2 75 167 60 35 95 28 5 23 4 45 49 74 165*2 592 34 93'2 46 73 163'4 58'4 33 914 7 194 47 72 1616 32 89*6 25.6 8 64 48 54'4 384 71 159*8 56 8 31 878 24*8 9 7'2 49 56'2 70 158 30 10 14 8 104 96 67 1526 536 27 80'6 13 104 26 14 112 65 149 52 25 77 20 15 5 12 64 1472 512 24 16 3'2 128 63 1454 50'4 17 14 136 62 14386 49'6 22 18 61 14'4 141*8 4808 21 6968 16.8 19 2'2 152 Zero Fahrenheit corresponds with minus 1779 Centigrade, and minus 14:22 Réaumur. 576 176 15'8 392 WATER. per inch. IMMERSION IN SALT AND FRESH WATER. To find the difference of immersion or draught in salt and fresh water. If from salt to fresh, multiply the draught of salt water by 36, and divide the product by 35. If from fresh to salt, multiply the draught of fresh water by 35 and divide the product by 36. Example :--Required the draught of a vessel in fresh water when drawing 20ft in salt water : 20ft X 36 = 720 • 35st. = 20 5 in. Table of draughts worked out by the above formula : ΙΙο Yards depth. Yards depth, Average. Max. Average. Max. Atlantic 4,026 7,750 240 710 Pacific 4,252 9,310 English Channel. Indian 300 3,658 6,040 German 96 Arctic 1,690 5,300 72 Antarctic 3,000 45 Mediterranean 1,476 2,860 Baltic. 43 The Southern Ocean below Cape Horn reaches a depth of 5,500 yards, and off Cape of Good Hope, 5,700 yards. The average depth of the Bay of Biscay is 1,200 yards. BEAUFORT NOTATION, FORMULA, AS USED FOR INDICATING THE DISTURBANCE OF THE SEA. o Calm. 5 Rather Rough. TIME, AT FULL AND CHANGE, WHEN THE FOLLOWING LIGHTSHIPS SWING FROM FLOOD то EBB. . IT h. m 51 16 1 Bahama Bank 54 20 ON 4 12 own 45 2nd high water. Calshot 50 48 40 N I 16 45 W 10 25 Ist high water. 12 o and high water. Cardigan Bay 52 24 30 N 5 O 30 W IO 30 Carnarvon Bay 53 540 N 4 44 30 W 10 30 Cockle 52 41 20 N I 46 20 E 10 20 Corton 52 31 30 N I 49 30 E 10 451 (then N.N.E. at 8 Dudgeon 53 15 ONO 56 OE 7 O Turns Eastward at 7. East Goodwin 51 13 ONI 36 25 E 9 10 Uncertain. English & Welsh Ground. 51 26 30 N 2 58 O W 6 56 and high water. Galloper 51 45 ONI 55 50 E 12 0 Gull ONI 28 25 E 913 Hasbro 52 58 ONE 36 O E IO 30 Helwick 51 31 ON 4 24 OW6 o' and high water. Inner Dowsing 53 19 20 NO 34 20 E 7 o Turns Eastwd. at 7, N.E. at 9, N.N.W. at 12. Kentish Knock 51 39 30 N I 41 OEII 20' Slack lasts about 20 min. Leman and Ower.. 53 8 30 N 2 020 EIT 0 Lynn Well 53 I 25 NO 25 10 E 6 20 Morecombe Bay 53 54 OX 3 30 o W'10 30 and high water. Nab 50 42 15 NO 59 25 W 12 o About. Newarp 52 45 ONI 53 O E 10 30 (out from Sheerness. Nore.. 51 29 ON O 48 O E 12 30 The last 2 hours ebb, seis North Goodwin 51 19 30 N I 35 20 E 10 13 Uncertain. Outer Dowsing 52 28 15 NI 2 40 E 8 0 Turns Eastward at 8, Owers 50 38 35 NO 41 OW 10 35 About. (then N. at 9. Royal Sovereign 50 42 40 N O 26 50 E 10 45 Swings about 15 mins.be. Seven Stones. 50 3 50 N 6 4 30 W 5 o 2nd high water. [fore H. W Shambles 50 30 50 N 2 20 OW 10 20 Shipwash 52 I 30 N I 23 O ENI 10 Slack lasts about 40 mins. South Sand Head 51 9 12 N I 28 10 E. 9 o Uncertain. Spurn 53 34 ONO 13 OE 6 20 Sunk 51 50 40 N I 30 30 E 11 40 Slack lasts about 40 mins. Tongue 51 29 ON'T 19 20 E 12 15 Varne 50 56 10 N I 16 50 E 8 20 Uncertain. SPECIFIC GRAVITY OF DIFFERENT SUBSTANCES, COMPARED WITH WATER. 47 69 333 49 51 30 76 77 31° 68 704 32 331 68 889 68 900 68 912 68.923 68'934 68-946 68 953 550 57 35 58 81° 36 37 83 84 38 39 40 68.982 68'994 69 405 42 20 21 22 68° SPHEROIDAL TABLES, AND OF LONGITUDE IN MINUTES OF LATITUDE OR NAUTICAL MILES LATITUDE. Length of one Degree in Statute Miles. Lat. 46° 69 067 699 69*318 24 68-819 698079 70 69 326 25 68 828 69'092 71 бg'i04 72 69 341 27 68 848 69'116 73 69 348 28 68-858 69'128 74 69 335 29 68 868 69 140 75 69 361 68-879 69'152 69 367 €9'164 69 373 55 69-176 69 378 69-187 79 69 383 34 €9.198 80 69 387 69.210 69 391 13 69'221 82 69.395 14 69.231 69.398 68-970 61 69 401 16 62 бg'252 85 69 403 17 63 69'263 86 18 бg'ооб 649 69272 87 69-407 89 69'409 68 801 45 69'309 Length of one Degree in Nautical Miles. Lat. 699 21'521 24 55'125 41 '050 70 20'538 25 40'270 71 19 548 60*326 26 39 479 72 38.676 73 17'553 53'259 74 37.035 75 15.536 59'954 36 198 14 5+1 59 814 35'350 13.502 59-656 51 133 34492 12'478 33 50'562 33*623 79 11451 34 49'976 32 745 80 10 421 59'072 49 375 31856 81 13 58-841 48758 82 8:352 14 58 592 48'127 7313 15 58*325 47 481 61 29'135 46821 5230 57 737 46'146 63 27 278 86 3'140 25 388 88° 2'094 56722 43 24'432 89 I 047 21 56 348 44 43'313 23468 go o'o 22 42'571 68° 22 498 I.IGHTHOUSES. To find the height at which a Light should be put above the sea level to show a given number of miles : Multiply the number of miles by itself, and by 4, and divide the product by 7. Thus, a lamp required to show ten miles- 10 x 10= 100 x 4= 400 7) 557 feet. |