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the difference os which places are but 6 minutes,56 seconds.

And its North Latitude, as observed

deg. min. sec.

by Kepler was, 36 12 o

and by Ha/leys Computation 36 20 4

the difference of which Latitudes are 8 minutes4 seconds.

And out of 12 different observations made byKepler and others, when the undoubted errors intheir observations are set to rights, there is very lit-tle difference between them and Halley’s Compu-tations, and that difference which there is, thecandid reader will easily observe is to be attributedfor the most part to the observations, which arenot altogether congruous amongst themselves.

As to the period of one of the Comet’s revolu-tions exceeding the other by more than a year, hereminds the reader, that it is no more than whathe has demonstrated in his Tables of the PlanetSaturn , where one of that Planet’s revolutions is13 days longer than the other, and is the conse-quence of one of the Laws of Gravity explainedby Newton ; and this irregularity he fays, must beabundantly greater in a Comet which emerges 4times higher than Saturn ; and it is probable hefays, this irregularity which is not accurately known,may make the next expected return of this Cometsomething more than 76 years, and it may not beseen again till the end os the year 1758, or begin-ning of 1759; but this he leaves to the discussionof posterity.

That the Comet observed by Appian in 1531,which is next preceding that of 1607, was the

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