The Inquisitive Dr. _Wallis_, having in his lately printed _Hypothesis_ of Tides intimated, that he had reason to believe, that the _Annual Spring-tides_ happen to be rather about the beginnings of _Febr._ and _Nov._ than the two _AEquinoxes_, doth in a late Letter to the _Publisher_, written from _Oxford_ in _Aug._ last, desire, that some understanding Persons at _London_, or _Greenwich_, but rather nearer the Sea, or upon the Sea-shore, would make _particular_ Observation of all the _Spring-Tides_ (_New-Moon_ and _Full-Moon_) between this and the End of _November_; and take account of the _Hour_, and of the _Perpendicular height_: that we may see, whether those in _September_, or those of _November_ be highest: And it were not amiss, the Low waters were observed too. Which may be easily done by a mark made upon any standing Post in the Water, by any {298} Water-man, or other understanding Person, who dwells by the Water-side. 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 this _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_.) * * * * * _Considerations and Enquiries concerning _Tides_, by Sir _Robert Moray_; likewise for a further search into Dr. _Wallis's_ newly publish't _Hypothesis_._ 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?