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relpeft to the equinoctial and Solstitial Points of the Ecliptick.
These Considerations determined me ; and by the Contrivance and Direction of the same ingenious Perion, Mr. Graham, my Instrument was fixed up Augufi 19, 1717. As I had no convenient Place where I could make ufe of lb long a Telescope as Mr. Molyneux's, I contented my self with one of but little more than half the Length of his (viz. of about Feet, his being X4±) judging from the Experience which I had already had, that this Radius would be long enough to adjust the Instrument to a Sufficient Degree of Exactnefs, and I have had no Reafon since to change my Opinion: for from all the Trials I have yet made, I am very well satisfied, that when it is carefully rectified, its Situation may be securely depended upon to half a Second. As the Place where my Instrument was to be hung, in fome Measure determined its Radius, fo did it alfo the Length of the Arch, or Limb, on which the Divisions were made to adjust it: For the Arch could not conveniently be extended farther, than to reach to about 63° on each Side my Zenith. This indeed was Sufficient, since it gave me an Opportunity of making Choice of Several Stars, very different both in Magnitude and Situation; there being more than two hundred inferted in the Britijh Catalogue,that may be observed with it. I needed not to have extended the.. Limb So far, but that I was willing to take in Capella, the only Star of the first Magnitude that comes fo> near my Zenith.
My Instrument being fixed, I immediately began to observe such Stars as I judged most proper to
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give me light into the Cause of the Motion already mentioned. There was Variety enough of finall ones; and not less than twelve, that I could observe through ail the Seafons of the Year 5 they being bright enough to be seen in the Day-time, when nearest the Sun. I had not been long observing, before I perceived, that the Notion we had before entertained of the Stars being farthest North and South, when the Sun was about the Equinoxes, was only true of those that were near the folstitial Colure: And after I had continued my Observations a few Months, I discovered, what I then apprehended to be a general Law, observed by all the Stars, viz. That each of them became stationary, or was farthest North or South, when they pasted over my Zenith at fix of the Clock, either in the Morning or Evening. I perceived likewise, that whatever Situation the Stars were in with refpecct to the cardinal Points of the Ecliptick, the apparent Motion of every one tended the same Way, when they pasted my Instrument about the same Hour of the Day or Night ; for they all moved Southward, while they pasted in the Day, and Northward in the Night; fo that each was farthest North, when it came about Six of the Clock in the Evening, and farthest; South, when it came a-bout Six in the Morning.
Though I have since discovered, that the Maxima in most of these Stars do not happen exadtly when they come to my Instrument at those Hours, yet not being able at that time to prove the contrary, and Supposing that they did, I endeavoured to find out what Proportion the greatest: Alterations of Declination in different Stars bore to each otherj it being