I had intended to carry out another wander round the docks, but spotted this notice pinned to a board at the Docks entrance. Thought you might be interested:-
_______________________________________________________ MOON'S AGE TIME OF HIGH WATER _______________________________________________________ Days Days 1 16 5 past 12 o'clock 2 17 52 12 3 18 40 1 4 19 27 2 5 20 15 3 6 21 3 4 7 22 51 4 8 23 39 5 9 24 27 6 10 25 15 7 11 26 3 8 12 27 51 8 13 28 39 9 14 29 27 10 15 30 15 11 _________________________________________________
The day of the month answering to the age of the moon, may be found by any
common almanack.
The height of the spring tides varies from about 17 feet to 21 feet; on
particular occasions they rise 3 or 4 feet higher.
When the sun and moon are
both nearest the earth, the tides are at a maximum; and especially if the
wind blow in the direction of the tide.
A combination of these circumstances
will sometimes accelerate the coming of the tide nearly an hour. Contrary
effects will retard it by a like interval.
Other circumstances being the
same, the tides augment and diminish with the moon's parallax, but in a
greater ratio.
Note: If from the time of high water at London, given in
White's Ephemeris, 3h. 25m. be subtracted, it will give the time of high
water at Liverpool
W. Marrat.
I always thought that I was reasonably well educated, but this notice has
bemused me completely. I had hoped to have another look at it when I went to
look at some more Sailing Ships, but we had a heavy thunder storm which
ripped the notice off the board ~ so we will never know how to work the
tides out! The one thing that does bother me is that I always thought a
lunar month was 28 days. If the table refers to a calendar month, were is
day 31?
Enough of this it's taxing the little grey cells!