BRITISH ALMANAC OF THE SOCIETY FOR THE DIFFUSION OF USEFUL FOR THE YEAR OF OUR LORD Price One Shilling; or, Four Shillings bound in cloth with the "Companion." EXPLANATORY NOTICES. Thermometrical Register. THE Thermometrical Register, showing the highest and lowest temperature of the corresponding month of the preceding year, has been resumed in the British Almanac this year at the request of numerous correspondents. These registers are copied from those made at the Royal Observatory, Greenwich. They show the highest and lowest ranges within each twenty-four hours, from self-registering thermometers. Each month is placed with its corresponding month, as affording the most ready and advantageous means of comparison, although by this arrangement the register of the last three months of 1873 follows the nine months of 1874, which are all that can be given up to the day of publication. Equation of Time. In this Almanac the calculations are all made for mean time (given by the clock), instead of apparent time (given by the sun-dial), which latter had been used up to the year 1833. It must be obvious that, for all practical purposes, mean time is the most useful; and to obtain it from apparent time, the columns in the Almanac headed "Equation of Time" should be used. The column "Equation of Time" ought, for example, to be consulted when persons are desirous of setting their clock by a sun-dial. When clock after sun is written above the number of minutes and seconds opposite to the day, then the clock ought to be set so much slower than the sun-dial, and the contrary. Moonlight. THE "Moon's age" is set down in days and the nearest tenths of days from the time of change. Thus it is New Moon on the 6th of April at 6h. 36m. morning, and therefore at noon of that day she is 5h. 24m. old, which is set down as two-tenths. The fraction of the day of course continues the same throughout the lunation. See also the table on page 10 showing the duration of moonlight. VARIATION OF THE COMPASS, or the declination of the magnetic or mariner's needle from the meridian or true north and south line at the undermentioned places in the United Kingdom, estimated for the year 1875. N.B.-The variation is westerly, that is, the magnetic pole is west of the true north pole, and is found to be decreasing in the United Kingdom about 9' annually. Scilly Islands, 21° 44'; Falmouth, 21° 26'; Plymouth, 21° 0'; Portland, 20° 14'; Portsmouth, 19° 44'; Brighton, 19° 12'; Dover, 18° 37'; London, 19° 16'; Yarmouth, 18° 49'; Sunderland, 21° 10′; Edinburgh, 22° 37'; Glasgow, 23°24'; Liverpool, 21° 34'; Pembroke, 22° 4'; Holyhead, 22° 29′; Dublin, 23° 31′; Belfast, 23° 49′; Galway, 24° 59'; Cork, 24° 6'. AUXILIARY TABLE FOR FINDING THE TIME OF SUNRISING AND SETTING. The time of Sunrise and Sunset in the 'British Almanac' is adapted to the parallel of latitude in which London is situate-viz., 51° 30'. THE table, pages 3-4, has been constructed to show the variations of time through the United Kingdom-namely, between the latitude of 58° and 50° 10' N. The times of sun-rising and sun-setting are computed for the instant that the sun's centre is even with the horizon of the sea. The number of minutes found in this table under the month-day, and in the required latitude, are to be applied to the time of sun-rising and setting found on that day in the Almanac; the result will be the time of his rising and setting at the place required.-Ex. At what time will the sun rise and set on May 21 at Edinburgh? The times of sunrise and sunset on that day in the Almanac are 4h. 2m. A.M., and 7h. 51m. P.M. In the table, in parallel of 56°, in which (p. 3) Edinburgh is found, and under May 21, are 23 minutes; which, subtracted from 4h. 2m., leaves 3h. 39m. for time of sunrise; and, added to 7h. 51m., gives 8h. 14m. for time of sun-setting. But at those places where instead of mean time at place* railway time is now used, which in Great Britain is Greenwich mean time, and in Ireland Dublin mean time, to the times of sun-rising and sun-setting, as deduced by the auxiliary table, the longitude in time must be applied thus:-For places in Great Britain whose longitude is west of Greenwich, to the time of sunrise or sunset add the longitude in time, and for places whose longitude is east of Greenwich, subtract the longitude in time, the result will be the railway or Greenwich time that the sun rises or sets. N.B.-Longitude in arc, indicated by the signs °" (degrees, minutes, and seconds) is converted into longitude in time by reckoning 360° 24 h., 15° = 1 h., and 1°4m. Example:-On June 21st at Penzance, in latitude 50° 7' N. and longitude 5° 31′ W., what will be the railway time that the sun rises and sets? *See above, Explanatory Notices, Equation of Time. At London, or in lat. 51° 30', by Calendar, page 25.. 3 44 Longitude in time...................... Railway or Greenwich mean time 3 52 add 22 4 14 ...... 8 32 The places which follow the different parallels hereunder stated are situate within 15 miles of latitude, either north or south of it. 58° 0'-Dornoch, Tain, Dunrobin, Portenleik, Dunclaim. 57° 30'-Peterhead, Fraserburg, Banff, Elgin, Cromarty, Inverness, Applecross. 57° 0'-Aberdeen, Bervie, Braemar, Laggan, Corpach. 56° 30'-Forfar, Dundee, Perth, Comrie, Ardchattan. 56° 0'-Berwick, Haddington, Edinburgh, Linlithgow, Kinross, Stirling, Dumbarton, Glasgow. 55° 30'-Embleton, Jedburgh, Selkirk, Sanquhar, Lanark, Irvine, Ayr. 55° 0'-Newcastle, Morpeth, Carlisle, Annan, Dumfries, New Galloway, Wigton. 54° 30'-Scarborough, Whitby, Hartlepool, Stockton, Richmond, Appleby, Cockermouth, Whitehaven, North part of Isle of Man. 54° 0'-New Malton, York, Aldborough, Clitheroe, Lancaster, Preston. 53° 30'-Grimsby, Kingston-upon-Hull, Pontefract, Manchester, Wigan, Liverpool, Beaumaris, Holyhead. 53° 0'-Lynn Regis, Boston, Lincoln, Nottingham, Derby, Stafford, Flint, Chester, Denbigh, Caernarvon, Harlech. 52° 30'-Birmingham, Yarmouth, Norwich, Thetford, Ely, Peterborough, Leicester, Coventry, Lichfield, Shrewsbury, Ludlow, Montgomery, Aberystwith. 52° 0'-Ipswich, Colchester, Cambridge, Hertford, Bedford, Buckingham, Oxford, Gloucester, Worcester, Hereford, Monmouth, Brecon, Caermarthen, Cardigan, St. David's. 51° 30'-LONDON, Ramsgate, Canterbury, Rochester, Chelmsford, Windsor, Wallingford, Marlborough, Malmesbury, Bath, Bristol, Newport, Cardiff, Llandaff, Pembroke. 51° 0'-Dover, Winchelsea, Brighton, Guildford, Chichester, Winchester, Portsmouth, Southampton, Salisbury, Shaftesbury, Wells, Ilchester, Taunton, Bridgewater, Minehead, Barnstaple. 50° 30′-Newport (I. W.), Poole, Weymouth, Exeter, Ashburton, Totnes, Plymouth, Tavistock, Launceston, Bodmin, Camelford, Padstow. 50° 10'-Truro, Falmouth, Helston, Penzance. IRELAND. 55° 0'--Carrickfergus, Antrim, Coleraine, Londonderry, Lifford, St. Johnstown. 54' 30'-Belfast, Killyleagh, Downpatrick, Armagh, Charlemont, Dungannon, Augher, Donegal, Ballyshannon, Enniskillen, Sligo. 54° 0'-Carlingford, Newry, Dundalk, Drogheda, Kells, Cavan, Belturbet, Carrick, Boyle, Castlebar, Killala. 53° 30′-Dublin, Swords, Naas, Athboy, Mullingar, Philipstown, Kilbeggan, Athlone, Roscommon, Lanesboro', Tulsk, Tuam, Ballinrobe. 53° 0'-Wicklow, Blessington, Baltinglass, Carlow, Athy, Kildare, Portarlington, Maryborough, Ballinakill, Banagher, Galway, Ennis. 52° 30'-Newborough, Enniscorthy, Wexford, Kilkenny, Cullen, Clonmel, Cashel, Killmallock, Limerick, Askeaton. 52° 0'-Waterford, Dungarvon, Youghal, Tallow, Lismore, Rathcormack, Cork, Mallow, Killarney, Tralee, Ardfert, Dingle. 51° 30'-Kinsale, Bandon, Clonakilty, Baltimore. LIST OF THE CORRESPONDENCE OF ERAS WITH THE YEAR 1875. [In those Bras which begin with the Christian year, the year alone is stated; in those which begin at a different season, the month in which the 1st of January, 1875, occurs is also given.] Correspondence with 1875. Abbreviations. |