Page:Philosophical Transactions - Volume 004.djvu/184

 hands. The Subject being Curious and weighty, it was thought fit to advertise the Inquisitive Reader, though somewhat late, of what is discoursed upon it by other Learned men, besides those those whom we have formerly noted.

This Author then doth principally discourse of the Motion and Place of that Comet, and how its odd Appearances may be salved; and in regard that in such a Discourse of the Motion of a Body, seen in the Heavens, 'tis requisite to suppose the Form and Constitution of the Celestial Bodies, and in what manner they make their Revolutions. He thought it requisite, suppose, either to choose some or other of the most famous Hypotheses concerning them, or else to endeavor to solve the Phænomena of this Comet, according to all those Systems: Of which two Tasks he hath chosen the latter; in the prosecution, whereof he seems satisfied, that the Comet of 1664. was above the Moon, it having been found without a sensible Parallax; for the observing of which, he shews an easie way, which needs no Quadrants or Sextants curiously made; nor a precise taking of the Meridian Altitudes; nor the Scituation of the Comet in the Zodiack; not the noting of the precise time of the Observation; nor lastly, needs to fear to be prejudiced by the Consideration of the various Refractions; forasmuch as he works not by the way of taking the several Altitudes from the Horizon, but by observing the Position of the Comet among some neighbouring Fixt Starts: for the doing of which, he saith, he employed only a simple Thread stretch't out by an Arch, to make it evident, whether this Comet had a sensible Parallax, or no.