Tides

[peterb]

Reeds give a Mean level for Lulworth Cove of 1.2m. I know the tides in the Bristol channel are due to the geography but I find it interesting that tides can vary within a relatively short distance.
Allan

Chart 5058 gives co-tidal and co-range curves for the UK and adjacent waters. A co-tidal line joins places with the same tidal times; a co-range curve joins places with the same range. At 'amphidromic points' all the co-tidal curves meet; think about it, the only way by which you can have high tide at all times is if there is no tide. 5058 shows amphidromic points just off Stavanger, in Norway; near Islay in Scotland; between Lowestoft and Hoek van Holland; and about 100nm west of Esbjerg. There is also a degenerate system with the co-tidal curves converging a few miles north-west of Poole; that's why the range is so small at Poole, and why the times change so rapidly between Poole and Lulworth.

And a vote for the Admiralty Manual of Tides (NP120). It's quite mathematical, it's old-fashioned, and it's a pig to read, but it's got more hard information than any other book on the subject.

 

[guernseyman]

I guess the first correct explanation of tides is probably in Newton's Principia! However, as it is in Latin, it is not very accessible these days

It's a pity to make appear inaccessible one of the great books of the world.

Here is a downloadable text in English:

http://www.archive.org/details/newtonspmathema00newtrich

 

[AntarcticPilot]

It's a pity to make appear inaccessible one of the great books of the world.

Here is a downloadable text in English:

http://www.archive.org/details/newtonspmathema00newtrich

NEWTON wrote in Latin, the academic lingua franca of the day. It was, of course, translated shortly after publication; well within Newton's lifetime. However, even in English it is pretty inaccessible because Newton's notation for calculus was not widely adopted, and the English is that of the 17th century. I agree it is a very great work!

 

[guernseyman]

NEWTON wrote in Latin, the academic lingua franca of the day. It was, of course, translated shortly after publication; well within Newton's lifetime. However, even in English it is pretty inaccessible because Newton's notation for calculus was not widely adopted, and the English is that of the 17th century. I agree it is a very great work!

Hey! I know you English hate intellectuals, even your own, but Newton was actually a bast ard after your own hearts.

What have you got against his book though? The downloadable translation, for which I gave the link, may be of American origin but it is in the English of the 19th century. It is readable.

 

[AntarcticPilot]

Hey! I know you English hate intellectuals, even your own, but Newton was actually a bast ard after your own hearts.

What have you got against his book though? The downloadable translation, for which I gave the link, may be of American origin but it is in the English of the 19th century. It is readable.

I have nothing whatsoever against his book, which is one of the most sublime pieces of genius ever. We have no argument about that; I am not intending to detract from Newton's pre-eminence at all.

But it IS inaccessible to a 20th century reader, for several reasons, none of which detract from its greatness! The first is simply that Newton's notation bears little resemblance to anything used today; we use Leibnitz' (I think) notation, which is more intuitive to use. I do recall a few remnants of Newton's notation (the "dot" notation for differentiation) still hanging on grimly 40 years ago - but even then, they weren't mainstream. The second is that the conventions of literature have changed, so that a 17th century work of any kind is harder to read than the equivalent from the 20th century. Try reading Swift or Defoe - while they are gripping and engaging once you've got used to them, it takes quite a while to get used to them - and they started out in English! The material he covers is not material most people are familiar with unless they did at least high school physics and maths. And finally, he uses Euclidean geometry extensively, and this is not taught in modern maths syllabuses (at least, it isn't in the UK, since about the time I did A-levels). And the Euclidean geometry of conic sections is something that only specialized mathematicians are likely to know these days.

One very interesting thing is that Newton himself thought his theological work (which is completely forgotten and ignored these days) was far more important than Principia, which he had to be encouraged to publish by (amongst others) Halley!

 

[jax]

I've spent the last 25 years sailing dinghys on a mine dump lake near Johannesurg,the
Med In the Ionian and the coast of Turkey and the East coast of the USA between N York and the Bahamas ------ Wots all this about 30 foot+ tides then?

 

[dvideohd]

A huge and useful resource...

Tides are a powerful source of energy - for desalinization and somewhat for power... It is going to be interesting to see how this plays out over time...

any tide over 10m sets up the potential for a vast water desalinization facility. I have not seen anyone work on this type project - (I am, though) and wonder if there is talk in the UK about it...

It's a truly abundant resource, if played with the environment right...

---jerry

 

[armchairsailor]

And I believe there is somewhere in the middle of the North Sea with no change in height at all. I used to know the long Latin or Greek name for it.

http://en.wikipedia.org/wiki/Amphidromic_point