Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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              equilibrated, and in their greateſt curvity, one while with
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              their convexity towards the upper part, and another while
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              towards the lower part of the Solar
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              Diſcus.
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              And becauſe
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              thoſe poſitions are in continuall alteration, making the
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              clinations and incurvations now greater, now leſſer, and
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              times reduce themſelves, the firſt ſort to perfect libration, and
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              the ſecond to perfect perpendicularity, it is neceſſary to aſſert that
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              the ſelf ſame Axis of the monethly revolution of the ſpots hath
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              a particular revolution of its own, whereby its Poles deſcribe
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              two circles about the Poles of another Axis, which for that
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              ſon ought (as I have ſaid) to be aſſigned to the Sun, the
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              ameter of which circles anſwereth to the quantity of the
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              nation of the ſaid Axis. </s>
              <s>And it is neceſſary, that the time of its
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              Period be a year; for that ſuch is the time in which all the
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              pearances and differences in the courſes of the ſpots do return.
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              </s>
              <s>And that the revolution of this Axis, is made about the Poles of
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              the other Axis parallel to that of the Ecliptick, & not about other
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              points, the greateſt inclinations and greateſt incurvations, which
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              are always of the ſame bigneſs, do clearly prove. </s>
              <s>So that finally, to
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              maintain the Earth fixed in the centre, it will be neceſſary to
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              ſign to the Sun, two motions about its own centre, upon two
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              ral Axes, one of which finiſheth its converſion in a year, and the
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              other in leſſe than a moneth; which aſſumption ſeemeth, to my
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              underſtanding, very hard, and almoſt impoſſible; and this
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              pendeth on the neceſſity of aſcribing to the ſaid Solar body two
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              other motions about the Earth upon different Axes, deſcribing
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              with one the Ecliptick in a year, and with the other forming
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              rals, or circles parallel to the Equinoctial one every day:
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              whereupon that third motion which ought to be aſſigned to the
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              Solar Clobe about its own centre (I mean not that almoſt
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              monethly, which carrieth the ſpots about, but I ſpeak of that
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              ther which ought to paſſe thorow the Axis and Poles of this
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              monethly one) ought not, for any reaſon that I ſee, to finiſh its
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              Period rather in a year, as depending on the annual motion by
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              the Ecliptick, than in twenty four hours, as depending on the
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              diurnal motion upon the Poles of the Equinoctial. </s>
              <s>I know, that
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              what I now ſpeak is very obſcure, but I ſhall make it plain unto
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              you, when we come to ſpeak of the third motion annual,
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              ed by
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              Copernicus,
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              to the Earth. </s>
              <s>Now if theſe four motions, ſo
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              incongruous with each other, (all which it would be neceſſary to
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              aſſign to the ſelf ſame body of the Sun) may be reduced to one
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              ſole and ſimple motion, aſſigned the Sun upon an Axis that never
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              changeth poſition, and that without innovating any thing in the
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              motions for ſo many other cauſes aſſigned to the Terreſtrial
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              Globe, may ſo eaſily ſalve ſo many extravagant appearances in </s>
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