Page:Philosophical Transactions - Volume 001.djvu/22

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suggest what I have taken notice of in my reflexions upon former Comets, which is, that more of them enter into our Systeme by the sign of Libra and about Spica virginis, than by all the other parts of the Heavens. For, both the present Comet, and many others registred in History, have entred that way, and consequently passed out of it by the sign Aries, by which also many have entred.

I did found my Hypothesis upon three Observations only, viz. those of the 22, 26, and 31. of December. Nor have I done, as some have fancied of me, who having been able to observe the Comet, the 27, 28, 29, 30, and 31. of December, and to see the diminution of its motion, have judged, that I had only determined that diminution for the time to come, conform to the augmentation thereof in time passed until the 29. of December. For January 1. (on which day I composed my Ephemerides) I knew not (nor any person here) that the motion of the Comet did diminish; but on the contrary, most men believed, it was not the same Comet. But Signior Cassini knows very well, that that was not necessary, seeing that two portions of a Tangent being given, and the Angles answering thereunto, 'tis easie to find the position and magnitude of its circle. The reason, which I think the true one, of the diminution of its Motion in Longitude, and of its Retrogradation, by me conjectured in my Ephemerides, I began to be assured of, Febr. 10. For until the sixth, the Comet had alwaies advanced, as Signior Cassini also hath very well noted: but after that day, I found that it returned in augmenting alwaies its Latitude. And I have constantly observed it, until March 8. between many Stars, which must be the same with these mentione'd by Cassini, whereof the number was so great, that I think, I saw of them March 6. with one Aperture of my Glass, more than 40. or 50. and especially, above the head of Aries; but I did not particularly note the situation of more than 12. or 15; amongst which I have observed the position of the Comet since January 28. every day, when the weather did permit, viz. January 29. February 3, 6, 10, 17, 19, 24, 26, 27. and March 6,

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7, 8.