VARIABLE STARS, 



m 



Tapm VIII, 



Tiblc of thege- 

 necal affe^liohs' 

 of the variaUo 

 ftar. 



: ,3 t- 



The author having thus fettled with confiderableprecifiori The changes In 

 thefe efiential variations of the ftar, proceeds to examine tome ^^ occafion 

 of its other phenomena, particularly one which is common to the periods 

 mol\ of the changeable ftars, and Tilcewife in fome degree ^^ l^ffj f ^^ ^^-u 

 our fun, namely, that the times of their periodical returns of other, 

 brightnefs are in general irregular, — a circumftance fo inte- 

 reftlng as to engage our attention, and which induced Mr. P. 

 io make the fuccefllon of obfervations, in the hope of difco- 

 vering its nature and cauie. With this view he has proceeded 

 to tabulate the feries of years, ib as to afcertain the apparent 

 rotations in days from the bbferved middle times,of its full- ^ 



brightnefs, and alfo from the obferved middle times of its 

 leaft brightnefs, for fingle periods. From thefe it appears, 

 that the periodical returns of brightnefs are uncommonly fluc- 

 tuating, and that the differences between the extremes are 

 very conliderable ; to account for which he offers tlie follow- 



VoL. XL— August, 1805. T ing 



