Bradley J. Account of a new discovered motion of the Fix'd stars // Phil. Trans. 1728. 35. Р. 637-641.

Bradley J. Account of a new discovered motion of the Fix'd stars // Phil. Trans. 1728. 35. Р. 637-641.

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Seafons of the Year. Upon comparing the Observations with each other, it was discovered, that in both the fore-mentioned Stars, the apparent Difference of Declination from the Maxima, was always nearly proportional to the versed Sine of the Sun’s Distance from the Equino&ial Points. This was an Inducement to think, that the Cause, whatever it was, had fome Relation to the Sun’s Situation with refpe<St to those Points. But not being able to frame any Hypothecs at that Time, sufficient to iblve all the Phenomena, and being very desirous to search a little farther into this Matter; I began to think of erecting an Instrument for my self at Wanjled, that having it always at Hand, I might with the more Ease and Certainty, enquire into the Laws of this new Motion. The Consideration likewise of being able by another Instrument, to confirm the Truth of the Observations hitherto made with Mr. Molyneux's, was no finall Inducement to me; but the Chief of all was, the Opportunity I should thereby have of trying, in what Manner other Stars were affe&ed by the same Cause, whatever it was. For Mr. Molyneux's Instrument being originally designed for observing y ^Draconis (in order, as I said before, to try whether it had any sensible Parallax ) was fb contrived, as to be capable of but little Alteration in its Direction, not above feven or eight Minutes of a Degree : and there being few Stars within half that Distance from the Zenith of Kew, bright enough to be well observed, he could not, with his Instrument, throughly examine how this Cause affetfted Stars differently situated with


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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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