306. And thus it appears, that as the Tides are governed by the Moon, they must turn on the Axis of the Moon’s orbit, which is inclined 23-1/2 degrees to the Earth’s Axis at a mean state: and therefore the Poles of the Tides must be so many degrees from the Poles of the Earth, or in opposite points of the polar Circles, going round these Circles in every lunar day. ’Tis true that according to Fig. IV. when the Moon is vertical to the Equator _ECQ_, the Poles of the Tides seem to fall in with the Poles of the World _N_ and _S_: but when we consider that _FHG_ is under the Moon’s orbit, it will appear, that when the Moon is over _H_, in the Tropic of Capricorn, the north Pole of the Tides, (which can be no more than 90 degrees from under the Moon) must be at _c_ in the arctic Circle, not at _N_; the north Pole of the Earth; and as the Moon ascends from _H_ to _G_ in her orbit, the north Pole of the Tides must shift from _c_ to _a_ in the arctic Circle; and the South Pole as much in the antarctic. It is not to be doubted, but that the Earth’s quick rotation brings the poles of the Tides nearer to the Poles of the World, than they would be if the Earth were at rest, and the Moon revolved about it only once a month; for otherwise the Tides would be more unequal in their heights, and times of their returns, than we find they are. But how near the Earth’s rotation may bring the Poles of it’s Axis and those of the Tides together, or how far the preceding Tides may affect those which follow, so as to make them keep up nearly to the same heights, and times of ebbing and flowing, is a problem more fit to be solved by observation than by theory. [Sidenote: To know at what times we may expect the greatest and least Tides.]