304. When the Moon is in the Equator, the Tides are equally high in both parts of the lunar day, or time of the Moon’s revolving from the Meridian to the Meridian again, which is 24 hours 48 minutes. But as the Moon declines from the Equator towards either Pole, the Tides are alternately higher and lower at places having north or south Latitude. For one of the highest elevations, which is that under the Moon, follows her towards the same Pole, and the other declines towards the opposite; each describing parallels as far distant from the Equator, on opposite sides, as the Moon declines from it to either side; and consequently, the parallels described by these elevations of the water are twice as many degrees from one another, as the Moon is from the Equator; increasing their distance as the Moon increases her declination, till it be at the greatest, when the said parallels are, at a mean state, 47 degrees from one another: and on that day, the Tides are most unequal in their heights. As the Moon returns toward the Equator, the parallels described by the opposite elevations approach towards each other, until the Moon comes to the Equator, and then they coincide. As the Moon declines toward the opposite Pole, at equal distances, each elevation describes the same parallel in the other part of the lunar day, which it’s opposite elevation described before. Whilst the Moon has north declination, the greatest Tides in the northern Hemisphere are when she is above the Horizon; and the reverse whilst her declination is south. Let _NESQ_ be the Earth, _NCS_ it’s Axis, _EQ_ the Equator, _T_♋ the Tropic of Cancer, _t_♑ the Tropic of Capricorn, _ab_ the arctic Circle, _cd_ the Antarctic, _N_ the north Pole, _S_ the south Pole, _M_ the Moon, _F_ and _G_ the two eminences of water, whose lowest parts are at _a_ and _d_ (Fig. III.) at _N_ and _S_ (Fig. IV.) and at _b_ and _c_ (Fig. V.) always 90 degrees from the highest. Now when the Moon is in her greatest north declination at _M_, the highest elevation _G_ under her, is on the Tropic of Cancer _T_♋, and the opposite elevation _F_ on the Tropic of Capricorn _t_♑; and these two elevations describe the Tropics by the Earth’s diurnal rotation. All places in the northern Hemisphere _ENQ_ have the highest Tides when they come into the position _b_♋_Q_, under the Moon; and the lowest Tides when the Earth’s diurnal rotation carries them into the position _aTE_, on the side opposite to the Moon; the reverse happens at the same time in the southern Hemisphere _ESQ_, as is evident to sight. The Axis of the Tides _aCd_ has now it’s Poles _a_ and _d_ (being always 90 degrees from the highest elevations) in the arctic and antarctic Circles; and therefore ’tis plain, that at these Circles there is but one Tide of Flood, and one of Ebb, in the lunar day. For, when the point _a_ revolves half round to _b_, in 12 lunar hours, it has a Tide of Flood; but when it comes to the