Page:Philosophical Transactions - Volume 001.djvu/325

 down the Times of the other, and the two Ebbs intervening, by subdividing the Differences, he assignes 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 Minut 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 pitch 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  ; The whole time of Flowing supposed to be 6. hours. But this Example will serve for marking the Spaces 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 easily be 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  being only set down as a Conjecture, flowing from Observations of the Motion of the water in its Rising and Falling, Rh