Page:Philosophical Transactions - Volume 001.djvu/311

 Water-man, or other understanding Person, who dwells by the Waterside.

It would also deserve (thinks he) to be inquired into, whether, when the Tides be highest, the Ebbs be ever lowest, & contra: (which is generally affirmed, and almost put out of question) or rather (which sutes best with his Hypothesis) whether, when the Tides are highest, both in the Annual and Menstrual Periods, the Low waters be not also highest; and at Neap-Tides, the Ebbes also very low.

He adds, that he should expect, that the Spring-Tides now coming, and those at the beginning of September, should not be so high, as those at the middle of September; and then lower again at the beginning of October, and after that, higher at the middle of October, and higher yet about the beginning of November (at the usual times of Spring-tides after the New and Full.)

In regard that the High and Low waters are observed to increase, and decrease regularly at several seasons, according to the Moons age, so as, about the New and Full Moon, or within two or three daies after, in the Western parts of Europe, the Tides are at the highest, and about the Quarter-Moons, at the Lowest, (the former call'd Spring-tides, the other Neap-tides;) and that according to the height and excesses of the Tides the Ebbes in opposition are answerable to them, the heighest Tide having the lowest Ebbe, and the lowest Ebbe, the highest Tide; the Tides from the Quarter to the highest Spring-tide increasing in a certain proportion; and from the Spring-tide to the Quarter-tide decreasing in like proportion, as is supposed: And also the Ebbes rising and falling constantly after the same manner: It is wished, that it may be inquired, in what proportion these Increases and Decreases, Risings and Fallings happen to be in regard of one another?

And 'tis supposed, upon some Observations, made in fit places, by the above-mentioned Gentleman, though, (as himself acknowledges) not thoroughly and exactly performed, that the Increase of the Tides is made in the Proportion of Sines; the first Increase exceeding the lowest in a small proportion; the next in a greater; the third greater than that; and so on to the mid-most, whereof the excess is greatest, diminishing again from that, to the highest Spring-Tide; so as the proportions, before and after the Middle, do greatly answer one another, or seem to do so. And likewise, from the highest Spring-tide, to the Lowest Neap-tide, the Decreases seem to keep the like proportions; the Ebbes rising and falling in like manner and in like proportions. All which is supposed to fall out, when no Wind or other Accident causes an alteration.

Rh