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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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


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very evident, that they did not all change their Declination equally. I have before taken notice, that it appeared from Mr. Molyneaux's Observations, that y 'Draconis altered its Declination about twice as much as the fore-mentioned finall Star almost opposite to it; but examining the matter more particularly, I found that the greatest Alteration of Declination in these Stars, was as the Sine of the Latitude of each refpe&ively. This made me suSpedt that there might be the like Proportion between the Maxima of other Stars ; but finding, that the Observations of fome of them would not perfectly cor-refpond with such an Hypothesis, and not knowing, whether the fmall Difference I met with, might not be owing to the Uncertainty and Error of the Observations, I deferred the farther Examination into the Truth of this Hypothesis, till I should be furnished with a Series of Observations made in all Parts of the Year; which might enable me, not only to determine what Errors the Observations are liable to, or how far they may safely be depended upon; but alfo to judge, whether there had been any sensible Change in the Parts of the Instrument itself.

Upon these Considerations, I laid aside all Thoughts at that Time about the Caufe of the fore-mentioned Phenomena, hoping that I should the easier difcovei it, when I was better provided with proper Means to determine more precisely what they were.

When the Year was compleated, I began to examine and compare my Observations, and having pretty well Satisfied my SelS as to the general Laws of the Phenomena, I then endeavoured to find out the



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