“From these remarks on the intire revolution of this Eclipse, we may gather, that a thousand years, more or less (for there are some irregularities that may protract or lengthen this period 100 years) complete the whole terrestrial Phenomena of any single Eclipse: and since 20 periods of 54 years each, and about 33 days, comprehend the intire extent of their revolution, ’tis evident that the times of the returns will pass through a circuit of one year and ten months, every _Chaldean_ period being ten or eleven days later, and of the equable appearances about 32 or 33 days. Thus, though this Eclipse happens about the middle of _July_, no other subsequent Eclipse of this period will return to the middle of the same month again; but wear constantly each period 10 or 11 days forward, and at last appear in Winter, but then it begins to cease from affecting us. “Another conclusion from this revolution may be drawn, that there will seldom be any more than two great Eclipses of the Sun in the interval of this period, and these follow sometimes next return, and often at greater distances. That of 1715 returned again in 1733 very great; but this present Eclipse will not be great till the arrival of 1820, which is a revolution of four _Chaldean_ periods: so that the irregularities of their circuits must undergo new computations to assign them exactly. “Nor do all Eclipses come in at the south Pole: _that_ depends altogether on the position of the lunar Nodes, which will bring in as many from the _expansum_ one way as the other; and such Eclipses will wear more southerly by degrees, contrary to what happens in the present case. “The Eclipse, for example, of 1736, in _September_, had its center in the _expansum_, and set about the middle of its obscurity in _Britain_; it will wear in at the north Pole, and in the year 2600, or thereabouts, go off into the _expansum_ on the south side of the Earth. “The Eclipses therefore which happened about the Creation are little more than half way yet of their etherial circuit; and will be 4000 years before they enter the Earth any more. This grand revolution seems to have been entirely unknown to the antients. [Sidenote: Why our present Tables agree not with antient observations.]