Required the Time of High Water at the Start Point, July 10, 1796? Epact 20 Day of Month 10 Num. of Month 5 Hence it appears that it is High Water at the Start at ten o'clock in the Afternoon. This is the Method of finding the Time of High Water inferted in common Books of Navigation, which, at Times, will give the Moon's Age whole Days, and the Time of her Southing, and of High Water, Hours wide of the Truth; and even if the Moon's Southing be exactly found, yet the Tides may differ lefs or more from the computed Time; for the Floods do not always happen at the fame Diftance of Time from each other, but at different Diftances, according to the Times of the Moon's Age, and her Afpect with Refpect to the Sun, or as the Waters are acted upon by the Sum or Difference of the attractive Forces of the Sun and Moon, and alfo on Account of Winds and Storms, even when out of Hearing, which greatly affected the Tides; the real Time of High Water at any Place will often differ from the computed Times; therefore Pilots and all concerned, would do well to ufe the following Method, which will, in general, give the Time of High Water within Half an Hour of the Truth, when the Tides are not greatly influenced by the Wind. A TABLE for the ready finding the Day of the Month the NEW MOON will fall on till the Year 1900, and confequently the Moon's Age, for any Day, by knowing the Golden Number, according to the Method commonly ufed for finding the Moon's Age.-Add to the given Year, and divide the Sum by 19, the Remainder will be the Golden Number, which, being marked with Pencil at the top of the Table, will fhew the Golden Number during that Year. Gn.No. Ja. Feb. Ma. Apr. May Ju. Jul. Au. Sep. O&. No. Dec. N MN MN MN MN MN MN MN MN MN MN MN M M. 0 44 I 22 1. 56 228 22 22 20 20 124 II 10 21.30 29 28 27 19 8 J7 17 8 9 25 25 13 10 15 14 11 16 Afternoon. 26.25 24 23 22 20 20 18 18 17 15 17 15 15 13 13 II ΙΟ 9 24 25 26 456 6 16 7 18 8 22 After Midnight. 00. 5 8 26 8།。 7 27 9 26 29 11 32 29111 12 From the Change to the Full, the Moon comes to the Meridian in the Afternoon; and fromthe Full to the Change, fhe comes to the Meridian after Midnight. The Ufe of the foregoing Tables. To find the Moon's Age, on any given Day, look in the first Column (marked Gn. No.) for the Golden Number, and under the Month, on the fame Line, ftands the Day of the New Moon; then count the Days which have completely paffed fince the laft Change, and they will be her Age on the given Day. To find the Time of High Water. Look for the Moon's Age in the Table of Times, and the Hours and Minutes oppofite to which being added to the Time of High Water, on the Change and Full Days, at any Place, will, if it does not exceed 12 Hours, give the Time of High Water there in the Afternoon of the given Day; but if it does exceed that Number, take 12 from it, and the Remainder will fhew the Time of High Water in the Morning. At what Time will it be High Water at London, April 29, 1796? Oppofite 11 the Golden Number, and under April, I find it was New Moon the 7th Day; and reckoning forward to April 29, gives 22 Days, for the Moon's Age. Against 22, in the Table of Times, ftand 4 Hours 36 Minutes, to which add 3 Hours, the Time of High Water at London on the Full and Change Days, and that gives 7 Hours 36 Minutes, the Time of High Water at London, in the Morning; differing one Hour from that found in the first Example by the common Method. Required the Time of High Water at Dover, October 12, 1796. Oppofite to 11 the Golden Number, and under October, I find it was New Moon the 1ft Day; reckoning forward to October 12, I find the Moon's Age is 11 Days; against II in the Table of Times ftand 8 Hours and 8 Minutes. This added to 10 Hours 30 Minutes, the Time of High Water on Full and Change Days at Dover, gives 18 Hours 38 Minutes; from which I take 12, and the Remainder 6 Hours 38 Minutes is the Time of High Water in the Morning at Dover on the given Day; differing from that found in the fecond Example by the common Method, 41 Minutes. EXAM PIE III. What Time will it be High Water at the Start, July 10, 1796? By the Tables it was New Moon the 4th Day, and reckoning forward to the 10th, I find there are 5 Days completely paft. Against 5 in the Table of Times, ftand 3 Hours 2 Minutes, which added to 6 Hours the Time of High Water at the Start, on Full and Change Days, gives 9 Hours 2 Minutes that Time of High Water in the Afternoon, on the above Day; differing from that given by the former Method, 58 Minutes. In like Manner may the Time of High Water be found at any other Place. Whoever will compare thefe Examples with the Methods ufed in other Books of this Kind, will find a confiderable Difference, as they frequently give the Moon's Age feveral Days, and of High Water, Hours wide of the Truth; indeed, on Account of the Irregularities in the Moon's Motion, the Times of her Change may differ half a Day from the Truth; and the Time of High Water 30 Minutes, but feldom more, if the Sea is not greatly influenced by the Wind. The Tides do not always answer to the fame Distance of the Moon from the Meridian, at the fame Places, but are varioufly affected by the Action of the Sun, which brings them on fooner when the Moon is in her first and third Quarters; and keeps them back later when she is in her second and fourth Quarters; because, in the former Cafe, the Tides raised by the Sun alone would be earlier than the Tide raised by the Moon; and in the latter Cafe later,* as may be seen in the Table of the Shifting of the Tides. As the Nautical Almanack is become now of general Ufe in long Voyages, the Time of High Water at any Part of the World may be readily found, if the Time making High Water at Full and Change be known; for in the fixth Page of each Month is given the Time of the Moon's Paffage over the Meridian of Greenwich every Day: This Time may be reduced to the Meridian of any other Place, by allowing 1 Hour for every 15 Degrees of Longitude. To this Time add the Time making High Water there, on Full and Change Days, which gives the Time of High Water nearly on that Day, if the Sum be lefs than 12 Hours; but if above, fubtract 12 Hours, or 24 Hours from it; obferving, that the Days in this Almanack begin 12 Hours later than the common Day. Among Pilots it is cuftomary to reckon the Time of Flood, or High Water, by the Point of the Compafs the Moon bears on at that Time, allowing three Quarters of an Hour for each Point. Thus, in Places where it is Flood at Noon on the Days of Full and Change, the Tide is faid to flow North and South, or at 12 o'Clock. In Places where the Moon bears 1, 2, 3, 4, or more Points to the Eaft or Weft of the Meridian, when it is High Water on the fame Days, the Tide is faid to flow on fuch a Point; fo if the Moon bears $. E. at Flood, it is faid to flow S. E. and N. W. or 3 Hours before the Meridian, that is, 9 o'clock; if fhe bears S. W. it flows S. W. and N. E. or at 3 Hours after the Meridian; and in like Manner for other Points of the Moon's bearing, as in the following Table.: * See Ferguson's Astronomy. ATABLE of the Bearings of the MooN at the Time of High Water, with the Time of thofe Bearings at the following Places: Ifle of Alderney, Gibraltar, Southamp or ton, Beachy, Sheernefs, a Sand called Kentifh Knock, a Sand called the Swin, at the Mouth of the Thames. 45 Minutes paft 12, Rochefter, Flushing, Malden, Nore. or 30 Minutes paft 1, Bell Iflé, Tinmouth, Gravefend, Holyhead, or 15 Minutes paft z, Berwick, Lisbon, St. Andrew's, Couquet. Whitby, London, Amfterdam, Bour Breft, Huntcliff, Ifle of Bas, at the Maes In Brefound, Ufhant, Seilly, Cork, C. Clear, Start Point. Hull, Wells, Weymouth, Plymouth, Briftol, Portland Road, Lynn, Foulnefs, Foy. Eddiftone, Yarmouth, Needles, Fly, Ifle of Man, Isle of Wight, E. End, Caf- N. Foreland, Dungeness, Dunnofe, Shoreham Margate, Harwich, Rofe, Pool, Portf Dunkirk, Embden, R. Elbe, Coaft of NOTE. The Current in the Downs generally runs 7 Hours to the North; and 5 Hours to the Southward; at Dover the Tide from the Channel runs Northward 7 Hours; and from the North 5 H. o M. at the Full and Change of the Moon. The Tides fet in the. Downs N. N. E. and S. S. W. Hourly. It is High Water at London 46 Minutes after Two at Full and Change by the Shore. Pilots reckon 6 Hours for a Tide, then as Tide is Hour, and half quarter Tide is if it flows Tide, half Tide, and quarter Tide, half an Hour after 10 o'Clock, which is the the Shore. a Tide is 3 Hours, of an Hour. So that it is High Water at Cafe in the Downs by |