Philosophical Transactions of the Royal Society Part 33

_LONDON_,

Printed for _John Martin_ and _James Alestry_, Printers to the Royal Society. 1666.

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_Numb._ 18.

PHILOSOPHICAL _TRANSACTIONS._

_Munday_, _October_ 22. 1666.

The Contents.

__Patterns_ of the _Tables_ proposed to be made for _Observing of Tides_; promised in the next foregoing _Transactions_. Other _Inquiries_ touching the Sea. Some Considerations touching the _Parenchymous_ parts of the Body. Observables concerning _Petrification_. A Relation from _Paris_, of a kind of _Worms_, that eat out Stones. Some promiscuous Observations made in _Somersets.h.i.+re_.

A Problem for finding the Year of the _Julian Period_, by a new and very easie Method. An Account of some Books, not long since publish'd, which are, _1. Tentamina Physico-Theologica de Deo_, Auth.o.r.e _Samuele Parkero. 2. Honorati Fabri Tractatus duo; Prior, de Plantis et de Generatione Animalium; Posterior, de Homine. 3. Relation du Voyage de l'Evesque de Beryte, par la Turquie, la Perse, les Indes_, &c. per Monsieur de _Bourges_._

__Patterns_ of the _Tables_ proposed to be made for _Observing of Tides_, promised in the next foregoing _Transactions_; by Sir _Rob. Moray_._

In performance of what was promised in the last of these _Papers_ for Observing the _Tides_, here are subjoyned _Patterns_ of the _Tables_ there mentioned; _One_, for marking the _precise Time_ of the High waters and Low-waters during one Month; that is, between _New_ and _New_ Moon, or _Full_ and _Full_ Moon. The _other_, for marking the _Degrees_ of the Risings and Fallings of the Water in _Equal_ s.p.a.ces of Time, and the _Velocity_ of its motion at _several_ heights: The _Degrees_ of _Heat_ and _Cold, &c._

The _Times_, a.s.signed in the _first_, to the High waters and Lowest Ebbs, are taken out of Mr. _Wing_'s Almanack, for this present year 1666, as he calculates them for the Month of _September_ for _London Bridge_. Only, whereas he takes notice but of _one_ High-water for every day, _Here_ are set {312} down the Times of the other, and the two Ebbs intervening, by subdividing the _Differences_, he a.s.signes between two Tides, equally amongst them. In all which, though there may be Errors, that is not to be considered, seeing the Dissein is to Correct and State the _Times_ of the _Tides exactly_ by _Experiments_, after this method. Mr. _Wing_ states the High waters to fall out at _London-Bridge_ constantly, when the Moon is 46.

deg. 30. min. to the _West-ward_ of the _Meridian_. For the Times, he marks for them, are made up by adding every day 3. hours, 6 minutes, to those in his _Table_ for knowing the Time of the Moons coming to the South.

The _First Table_ consists of _two_ Parts, and each part of _four Columns_.

The _first_ part marks the Tides and Ebbs from the day of the _New_-Moon to its _Full_: The _other_, from the _Full_ to the next _New_. The _first Column_ in both parts hath the day of the Month and Week; _M._ standing every where for _Morning_ and _A._ for _Afternoon_. The _third_ column hath the _Character_ of the day of the Week prefixt to the Hour and Minute of the High-water, and answering to the day of the Month. The _last_ Column hath the same for the time of Low-water, varying the _Character_ of the day, as often as the low-water falls out more early than the High-water. In this _Example_ between the said _New_ Moons there falls out in all just 57.

periods of the Tide or Flowing water, and 58. of the Ebb or Low water; which numbers vary according to the Intervals of the Moons changes, but with what constancy and exactness, is to be inquired after: Which whosoever undertakes to do, may keep such a _Table_, as is here proposed, in a Book by it self.

The _other_ Table doth in 9. _Columns_ comprehend the particular Observations of the _Degrees_ of the Rising and falling of the Tides, and the other things specified at the Tops of them: The _first_ Column marking the Hour and Minut common to all the several Observations. Each hour is divided in 3. equal Parts, that number of Observations being only pitch't upon by way of _Example_: The numbers may else be varied at pleasure, when other more frequent Observations are thought fit to be made, or when they prove too frequent and laborious; though the most frequent are most desirable, till competent information of all particulars be attained.

The _Rising_ of the Tide from Low-water to the highest pitcht of the full Sea, is here supposed to be 60. foot: And the Degrees of its rising every 20. Minuts, to be in the _Proportion_ of _Sines_, The whole time of Flowing supposed to be 6. hours. But this _Example_ will serve for marking the _s.p.a.ces_ of the Increasing or Rising, as well as of the falling of the water, in order to the investigation of their _Proportions_ to one another, when the _Duration_ of the Tide exceeds 6. hours by any number of _minuts_, as well as for just 6. hours; seeing they may be easily collected from any Number of Observations; their precise Time and that of the Duration of the waters Rising and Falling (that is, the just interval between the High-Water and Low-water) being known: This Calculation by _Sines_, being only set down as a _Conjecture_, flowing from Observations of the Motion of the water in its Rising and Falling, {313} which seems to observe this or some such like Proportion; which is supposed still to hold in _all_ Tides, be the _Duration_ what it will; the Increase still continuing proportionably till the very midle of the Hight and Duration, and Decreasing afterwards in the same manner: Which whether it be so indeed or not, is that, which is desired to be known.

There is the like Proportion here supposed to be in the _different degrees_ of the _Velocity_ of the Current of the Water after _Equal_ s.p.a.ces of Times, as in its Rising and Falling: And so it is markt in the _Third_ Column. But because the _true Velocity_ of the Current of the Water, raised above the Levell 456/1000 of a foot, is unknown, it is by way of Supposition set at Ten feet in one Minute of an Hour, which being once stated, the rest distant from each other by the s.p.a.ce of 20. Minutes of an Hour, are set down according to the same _Proportions_ of _Sines_ before suggested. It being supposed, that of the _Velocity_ of the Current of the Tide, after it hath flowed 20 minuts of an hour, be such, as a Log of Wood placed in the Water will move 10 foot in the s.p.a.ce of one minute of time, at the middle of the Tide it will in the like s.p.a.ce of Time move 114 f.

276/1000, and so proportionably at other times: Which, howsoever these Proportions shall be found by Experiments to fall out, may be not unworthy of the pains and charges requisite to acquire the knowledge of it. For, besides the satisfaction it may afford upon other accounts, it may possibly be of no small use to those, who need an exact reckoning of their s.h.i.+ps running, when the Velocity of the Current of the Tide may be necessary to be known; lest through the defect of the knowledge of that, especially when it is reckoned less than indeed it is, the s.h.i.+p be thrown in the night upon Sh.o.r.es, Rocks or Sands, when they reckon themselves to be far from them.

The Numbers in the 4, 5, 6, 7, and 8. _Columns_ are set down at random, only for _Examples_ sake; there being no difficulty in the apprehension of it, and imitating of it in setting down the true Hights and Variations of the _Thermometer_, _Baroscope_, &c. The Use whereof is so vulgarly known, that there needs no further Direction concerning them. But if any person who would make these Experiments, do not know the fabrick or use of any of the Instruments requisite for some of these Observations, nor where to have them, he may address himself to Mr. _Shortgrave_, one of the _Operators_ of the _Royal Society_, lodged in _Gresham Colledge_, from whom he will receive full satisfaction about these things.

But the labour employed in the Observations of the Heat, Cold, &c. required to be taken notice of in order to the Ends proposed in the former _Tract_, and others that may be of no less delight than advantage, will be much retrenched, when Dr. _Christopher Wren_ puts in practice, what he some years ago proposed to the _Royal Society_ concerning an _Engine_ with a _Clockwork_, which may perform these Observations in the last enumerate _Columns_, without being toucht or lookt after but once or twice a day.

The Tables themselves follow,

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_A Perpendicular Line divided into _Signes_, supposed to be the _Periods_ of the Risings and Fallings of the Tides, as is in the other Table represented._

[Ill.u.s.tration]

1666. Age of Time of High water. Time of Low water.

Sept. the moon ho.mi. Day. Hour. Min. Day. Hour. Min.

Mo. 3. New Mo. 2. 57. Morn. Mo. 9. 8. Morn.

8.38'. 3. 19. Aftern. 9. 30. Aftern.

Tu. 4. Tu. 3. 41. M. Tu. 9. 51 M.

4. 2. A. 10. 12 A.

We. 5. We. 4. 23. M. We. 10. 33 M.

4. 43 A. 10. 53 A.

Th. 6. Th. 5. 4. M. Th. 11. 14 M.

5. 25. A. 11. 35 A.

Fr. 7. Fr. 5. 46. M. Fr. 11. 56 M.

6. 7. A. Sa. 0. 17 M.

Sa. 8. Sa. 6. 28. M. 0. 39 A.

6. 51. A. Su. 1. 2 M.

Su. 9. Su. 7. 14. M. 1. 23 A.

7. 37. A. Mo. 1. 48 M.

Mo. 10. Mo. 8. 0. M. 2. 13. A.

8. 26. A. Tu. 2. 39. M.

Tu. 11. 1. Qu. Tu. 8. 52. M. 3. 5. A.

10 A. 9. 18. A. We. 3. 31. M.

Mo. 12. Mo. 9. 44. M. 3. 57 A.

10. 11 A. Th. 4. 25 M.

Th. 13. Th. 10. 39. M. 4. 53. A.

11. 7. A. Fr. 5. 21. M.

Fr. 14. Fr. 11. 35. M. 5. 49. A.

Sa. 15. Sa. 0. 3. M. Sa. 6. 17. M.

0. 31. A. 6. 45. A.

Su. 16. Su. 0. 59. M. Su. 7. 13. M.

1. 27. A. 7. 41. A.

Mo. 17. Mo. 1. 55. M. Mo. 8. 9. M.

2. 23. A. 8. 36 A.

Tu. 18. Full. Tu. 2. 50 M. Tu. 9. 4 M.

11.10'. 3. 19. A. 9. 31 A.

We. 19. We. 3. 45. M. We. 9. 58 M.

4. 11. A. 10. 25 A.

Th. 20. Th. 4. 39. M. Th. 10. 52 M.

5. 6. A. 11. 20. A.

Fr. 21. Fr. 5. 34. M. Fr. 11. 48. M.

6. 2. A. 0. 16. A.

Sa. 22. Sa. 6. 30. M. Sa. 0. 44. A.

6. 58. A. Su. 1. 12 M.