72 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



proceed the figures iu this coIuniD if we adopt the corrections presently to be spoken of, and 

 which leave the differences added in brackets. 



For the known stars modern determinations furnish the following positions, referred to the 

 equinox of 1700 : 



The difference a — T should be constant. Further, the observed zenit distance {per lineas 

 cUagonales, wbich Flamsleed always uses, in preference to that per sfrias cochlea') should result 

 when subtracting the declination from 51° 30' 38", which is the sum of 51° 26' 38" + 8' 40"— 40'' 

 (latitude of Greeuwich + index error — refraction). We get — 



The large errors remaining here, column 4, in the declinations of 96 and 101 Tauri have been 

 pointed out already by Baily (iu Notes to No. 611 and No. 642 of British Catalogue), without the 

 attempt of a conjecture as to their origin, the MS. entry showing no trace of mistake. I venture 

 to suggest lor the correct zenit distance record : 



96 Tauri 36° IC 20" 822.20 instead of 36° 11' 20" 820.20 

 101 Tauri 36° 10' 50" 820.06 instead of 36° 2' 50" 817.06. 



This rests upon the hypothesis, that of the strice cochleoe first were written only the fractions, 

 and the whole revolutions supplemented later so as to correspond with the respectively 5' and 8' 

 erroneous Unecc dlagonales. At least in the case of 96 Tauri the changes proposed are highly 

 probable. Converted into arc the screw readings are then 



822.20=36° 16' 44" and 820.06=36° 11' 5", 



leaving the differences from the Unece dlagonales of — 24" and — 15" respectively (the values in 

 brackets in the table above), in better agreement with the two other stars, and also, as seen from 

 the last table, iu good harmony with the computed zenit distances. 



Now, as to the disputed star, it must be between 96 and 101 Tauri. Here the following stars 

 are the only ones of sufticient brightness for i)ossible objects of Hamsteed's observations: 



