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tion of Declination is increased or diminished, as thofe Stars which lie near the Equinoctial Colure: I will give you alSo the Comparison between the Hypothesis and the Observations of n Ursae Majoris, that which was farthest South about the 17th Day of January 1728, agreeable to the Hypothesis. The following Table shews how much more Northerly it was found by Observation in Several Parts of the Year, and alSo what the Difference should have been according to the Hypothefis.
|
172*7. d. |
The Difference of Declination byOb-fervation. ^ |
The Difference of Declination by. the Hypothefis. • ^ |
1728. d. |
The Difference of Declination byOb-fervat'ion. |
SDH 3 S.aT i-5’a ^ P M. ^ O n' " * a cr P *•<1 0 «n // s '■ |
|
September - 14 |
z8i |
dpril - - 16 |
18 f |
18 | |
|
- - - 24 |
Hi |
Zfi |
May - - y |
24 i |
*3* |
|
Ottober — i<5 |
1 Pi |
191 |
'June - - f |
32 |
3 1 i |
|
November - 11 |
"i |
101 |
- - - zy |
3f |
34* |
|
December - 14 |
4 |
3 |
July - - 17 |
3<5 |
3^ |
|
1728 | |||||
|
February - 17 |
2 |
3 |
Jugufi - 2 |
3T |
3fi |
|
March - - 2; |
11* |
10' |
September - zo |
16] |
I find upon Examination, that the Hypothefis a-grees altogether as exadtly with the Observations of this Star, as the former; for in about fo that were made of it in a Year, I do not meet with a Difference of fo much as z<', except in one, which is
mark'd
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mark’d as doubtful on Account of the Undulation of the Air, &c. And this does not differ 3" from the Hypothefis.
The Agreement between the Hypothefis and the Observations of this Star is the more to be reguarded, since it proves that the Alteration of Declination, on account of the Proceflion of the Equinox, is (as I before SuppoSed) regular thro’ all Parts of the Year; fo far at least, as not to occasion a Difference great enough to be difcovered with this Instrument. It like-wiSe proves the other part of my former Supposition, •viz. that the annual Alteration of Declination in Stars near the Equinoctial Colure, is at this Time greater than a PreceSIion of 50" would occasion : for this Star was io" more Southerly in September 1718, than in September 17x7, that is, about x" more than it would have been, if the PreceSIion was but 50". But I may hereafter, perhaps, be better able to determine this Point, from my Observations oS those Stars that lie near the Equinoctial Colure, at about the same Distance Srom the North Pole of the E-quator, and nearly opposite in right Ascension.
I think it needleSs to give you the Comparison between the Hypothefis and the Observations of any more Stars; since the Agreement in the foregoing is a kind of Demonstration (whether it be allowed that I have difcovered the real Cauie of the Phenomena or not;) that the Hypothefis gives at least the true Law of the Variation of Declination indifferent Stars, with RefpeCt to their different Situations and Al-peCts with the Sun. And if this is the CaSe, it must be granted, that the Parallax of the fixt Stars is much fmaller, than hath been hitherto suppofed by thofe,
S ff f 2, who
