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XXXIII. On the Stars forming the Pleiades*. 



1 H E following catalogue contains a list of the 64 stars form- 

 ing the Pleiades given by M. Jeanrat in tlie Memoires de VAca- 

 dcmie des Sciences for 1779; and brought up to January 1, 1822, 

 in the manner hereafter mentioned. The importance of this 

 singular cluster of stars, at the present time, has induced me 

 to give a separate list of them. For, it is well known that the 

 moon is now in such a position, v>'ith respect to her nodes, as 

 to pass over the Pleiades every lunation in the present and se- 

 veral followmg years : thereby affording a favorable oppor- 

 tunity not only for such observations, but more particularly 

 for illustrating the theoiy of Cagnoli, with respect to his mode 

 of determining the figure of the earth, by means of occultations 

 of the fixed stars by the moonf. The passage of the moon 

 across the Pleiades has indeed at all times attracted the atten- 

 tion of astronomers ; as may be seen by the numerous obser- 

 vations recorded in the transactions of all the scientific so- 

 cieties, whenever the circumstance has taken place. In 1653 

 Kepler gave a chart of the Pleiades, in the sup]:)lement to his 

 Treatise on Optics: it consisted of 6 principal stars, and 

 26 smaller ones. In the Mem, de I'Acad. des Sciences there are 

 four charts by different authors: one by La Hire in 1693; 

 another by Cassini and Maraldi in 1 708 ; and another by 

 Outhier in 1770: but the most comprehensive one is that by 

 Jeaurat, as above mentioned, accompanied by a list of their 

 positions. This list, howevei', bears several inaccuracies on 

 the face of it : (v.hich indeed may be readily detected on a 

 close inspection of the original paper) and moreover the posi- 

 tions, when laid down on the chart, do not correspond exactly 

 with the present relative positions in the heavens. One re- 

 markable error pervades the whole of the original list. The 

 right ascensions in time exceed (by l" in time) the right as- 

 censions in arc. In forming the present table, however, I have 

 depended princi})ally ujion his Hst of dijfirenccs in ^'li and D 

 of the several stars from AleipneX: and the position of this 

 star (for the connnencement of the present year) I have dc- 

 tluced from Mr. Pond's catalogue of 400 stars. The mode, 

 by which M. .leaurat i()rnied his catalogue, was this: lie de- 

 termined the position of nine of the brightest stars, by means 



* From " Astronomical Tables and Remarks for the year 1822, by Francis 

 Daily, Fstj." a work printcil for private circulation only. 



\ Seir my translation of his Memoir on this subject. 



j This, it is evident, is not strictly correct, since the precession of the 

 jcveral star* will dilfur. lint, it will be siifliciently so in the present case, 

 where the original observations are suJ)jcct to so much uncertaintv. 



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