SECT. IV. YET in fome Places there are higher Tides at the Full Moon than at the New, which I cannot account for, unless they be the Effects of it's greater Light at that time. Nor can it be otherwife explained, why at the Full Moon Vegetables and Animals are impregnated with a greater quantity of Sea Moisture, than at the New, tho even then the Tides are every whit as high. It is very wonderful what one Twist, a Dutchman, relates in his Description of India, He fays, that in the Kingdom of Guzarai (where he lived many Years) their Oyfters, and Crabs, and other ShellFish, are not fo fat and juicy at the Full Moon as at the New, contrary to their Nature in all other Places. Nor is it lefs admirable, that on the Coast of the fame Kingdom, near the Mouths of the River Indus, the Sea fwells, and is troubled, at the New Moon, when not far from hence, viz. in the Sea of Calicut the greatest Rife of the Waters is at the Full. But it is requifite that we fhould have repeated Enquiries and Obfervations about these Matters, before we pretend to folve their Phænomena, . PROPOSITION XIII, The Flux and Reflux of the Sea varies with the Seafons of the Year, and the Tides are obferved to be bigbeft about the Equinoxes; i. e. at the Spring and Fall; but lowest at the Solstices, DES Cartes pretends to account for this Phenomenon by his Hypothefis, but I cannot ap prehend his Meaning by his Words, nor how it can be deduced from it (b). It is probable, that the Sun and the general Winds may contribute much (b) See the true Reafon of this in Artic. 3. of Note (f) above. to to raise these Tides, when, in the Equinoxes, the Sun is vertical to the Ocean in the middle of the Torrid Zone, and therefore may caufe both the Wind and Water to rage, and the former to a gitate the latter, The contrary of which may happen about the Solftices, Or we may fay, that thele extraordinary Tides then happen by the fame Reason, and proceed from the fame Cause that frequent Rains and Inundations proceed from in these Seafons. PROPOSITION XIV, In fome Parts of the Ocean, Bays, and Shores, the Tides ebb and flow very high; and in others but low: and in fome few Places there are no fenfible Tides at all. THOSE Places have the greatest Tides; 1, which are in the Torrid Zone between the Tropics, where the Moon, being almost constantly vertical, preffes the Water with greater force; 2. those which lie directly Eaft and Weft with their Collaterals; 3. thofe Bays that are long and narrow; 4. thofe Places where there are but few Iflands or Forelands. THE Tides are therefore greater or lefs in a Place, according as it is fituated or extended. THE greatest known Tides are obferved in the Bay of Guzarat, at one of the Mouths of the River Indus, and has ftruck many with Admira tion. The Water there recedes from the Shore very quick, and leaves it uncovered for a great Space; fo that this Bay is, not without Reason, thought to be the fame into which Alexander the Great failed, when he attempted to tranfport his Army by Sea into India, but was hindered, as it is reported, by the Sea which retired quick from SECT. IV. from the Shore, and left all his Ships a-ground, fo that he could not proceed further, but thought that the Gods had there fixed Bounds to his Expedition. This Story is reported for a Truth by the Inhabitants of Cambaya, The Caufe of this is the fhallownefs of the Chanel, which makes the Water in it's Ebbing leave fo much more Ground uncovered, tho' perhaps fome other Caufe may confpire with this. AT the Town of Daman, not far from Surat in India, the Tide rifes and falls two Fathoms and a half, and the Sea recedes from the Shore half a German Mile. IN the Bay of Cambaya the Tide flows five (or as fome fay feven) Fathoms high, which violent Flux caufes many Ships to be loft by unexperienced Seamen; for at the Ebb, when the Water falls back, they are frequently split upon the Rocks. UPON the Shores and Bays at the Magellanic Streights, there is no conftant Time obferved between the Tides, which ebb and flow irregularly, fometimes in three Hours, and fometimes in twelve Hours; which variety is caufed by the violent breaking of the Sea into thefe Streights, and the frequent Agitation of it by the Winds. PRODIGIOUS high Tides are obferved about Malacca, and in the Streights of Sunda. IN the Arabian Gulph, or Red-Sea, the Tide of Ebb is fo great, that as fome of the Antients have writ, (quoted by Scaliger) Mofes, and the Ifraelites, might, at low Water, have paffed thro it without a Miracle. But this is falfe, for, it never ebbs so much as to leave the Chanel dry. IN Button's Bay, near Hudson's Streights, when Mr Thomas Button, an Englishman, wintered there in the Latitude of 57 Degr. North Latitude, he obferved the Tide of Flood to rife fifteen Foot and above and in the Latitude of 60 Degr. the Summer after, he found it to come up to the fame Height;" tho' in neither Hudfon's nor James's Bay it rifes much above two Foot. THERE are prodigious high Tides upon the Coaft of China, and about the Inlands of Japan. AT Panama, a Town on the Coast of America, the Pacific Sea flows very high, and immediately ebbs again; at the Full Moon the Agitation is fo great that it drives the Water into the Houses of the Town. All along this Shore the Tides of the great South Sea are ftrangely high; fo that in their Reflux they retreat two Miles of Ground, and in fome Places the Water falls of out Sight. IN the Bay of Bengal, on the Shore of Siam, the Tide rifes fifteen Foot. BUT in the Mediterranean Sea, which flows from Weft to Eaft thro' the Streights of Gibralter, there is no fenfible Tide at all; because it's Entrance is fituated opposite to that Point, to which the Ocean Sea in general flows. It may perhaps Increase a little, but in the main it is not fenfible, only in the Gulph of Venice there is a fmall Agitation perceived, by reafon of the great length and narrowness of the Bay, which, in the broader Parts of the Mediterranean, is no where perceptible. Therefore the Flux and Reflux of the Sea was unknown to the Grecians, and alfo to the Romans in the Time of Scipio Africanus ; and therefore when they found it in other Places, accounted it a Miracle; as appears from the forementioned Expedition of Alexander the Great, and the Wars of Scipio with Carthage; but in Cicero's Time this was well enough known to the Romans. A fmall Tide is obferved at Marfeilles in France, and an inconfiderable Rifing is perceived along the Coast of Barbary. SECT. IV. IN the Baltic Sea, and all over the northern Ocean beyond England and Norway, the Tides are not in the least perceptible; nor in the northern Parts of the Pacific Ocean (i). The Reafon is not well known, unless we fix it upon the great Distance these Seas are from the way of the Moon, and their being extended from Weft to East, and North-eaft, with the many Islands and Forelands, all which confpire to obftruct the Flux of the Tides in thefe Places. But this cannot be faid of Hudson's Bay; which is properly extended from Eaft to Weft, to receive the Flux of the Tides; and therefore it is no Wonder if they are much more remarkable here than in the Baltic, or in the northern Ocean. PROPOSITION XV. The Flux of the Sea is forced by a strong Impulse but the Reflux is the natural Motion of the Water. THE Flux is caused by the Preffure of the Moon, or the celestial Matter, between it and the Sea, and continues no longer than the Cause forces it but in the Ebb, the Sea only flows from a higher to a lower Place, which is the natural Motion of the Water. (i) The Tides are very fmall in feveral Parts of the Northern Ocean, yet they may be felt in fome particular Places. Thus on the Coaft of Nova Zembla the LEMMA |