same point _a_ again in 12 hours more, it has the lowest ebb. In seven days afterward, the Moon _M_ comes to the equinoctial Circle, and is over the Equator _EQ_, when both Elevations describe the Equator; and in both Hemispheres, at equal distances from the Equator, the Tides are equally high in both parts of the lunar day. The whole Phenomena being reversed when the Moon has south declination to what they were when her declination was north, require no farther description. [Sidenote: Fig. VI. When both Tides are equally high in the same day, they arrive at unequal intervals of Time; and _vice versa_.] 305. In the three last-mentioned Figures, the Earth is orthographically projected on the plane of the Meridian; but in order to describe a particular Phenomenon we now project it on the plane of the Ecliptic. Let _HZON_ be the Earth and Sea, _FED_ the Equator, _T_ the Tropic of Cancer, _C_ the arctic Circle, _P_ the north Pole, and the Curves _1_, _2_, _3_, _&c._ 24 Meridians, or hour Circles, intersecting each other in the Poles; _AGM_ is the Moon’s orbit, _S_ the Sun, _M_ the Moon, _Z_ the Water elevated under the Moon, and _N_ the opposite equal Elevation. As the lowest parts of the Water are always 90 degrees from the highest, when the Moon is in either of the Tropics (as at _M_) the Elevation _Z_ is on the Tropic of Capricorn, and the opposite Elevation _N_ on the Tropic of Cancer, the low-water Circle _HCO_ touches the polar Circles at _C_; and the high-water Circle _ETP6_ goes over the Poles at _P_, and divides every parallel of Latitude into two equal segments. In this case the Tides upon every parallel are alternately higher and lower; but they return in equal times: the point _T_, for example, on the Tropic of Cancer (where the depth of the Tide is represented by the breadth of the dark shade) has a shallower Tide of Flood at _T_ than when it revolves half round from thence to _6_, according to the order of the numeral Figures; but it revolves as soon from _6_ to _T_ as it did from _T_ to _6_. When the Moon is in the Equinoctial, the Elevations _Z_ and _N_ are transferred to the Equator at _O_ and _H_, and the high and low-water Circles are got into each other’s former places; in which case the Tides return in unequal times, but are equally high in both parts of the lunar day: for a place at _1_ (under _D_) revolving as formerly, goes sooner from _1_ to _11_ (under _F_) than from _11_ to _1_, because the parallel it describes is cut into unequal segments by the high-water Circle _HCO_: but the points 1 and 11 being equidistant from the Pole of the Tides at _C_, which is directly under the Pole of the Moon’s orbit _MGA_, the Elevations are equally high in both parts of the day.