Latitudes of Monijouy and Barcelona. 243 



" duo parvi comites oct. mag., una supra, alter infra stellam 

 fere 10 V 



In 1779 — 1781, Sir Wm. Herschel measured their distance, 

 14".5. Piazzi in 1792 makes the smaller star 13".3 south of 

 the principal, and from the difference of A.R. and declination 

 their angular distance 1 5''.9. 



From that period to 1818, I do not know of any observa- 

 tions having been made ; but since 1818, the two stars have 

 been examined by MM. Struve, South, and Herschel, whose 

 measures agree in making their distance about 14".5. Lastly, 

 I myself, in 1827, by more than twenty observations with the 

 mural circle of Fortin at the observatory, find the lesser star 

 always 13" south of the principal. All these results, obtained 

 at periods so widely apart, and by means so different as 

 micrometers and meridian instruments, may in fact be regarded 

 as identical ; the little differences they present, being of the 

 order of possible errors of observation, cannot reasonably 

 be ascribed to the peculiar motion of stars, whose relative 

 position we find exactly the same in 1755, 1781, 1792, and 

 at the present time. In comparing the results, we find nothing 

 to authorise a belief that these stars have any mutual relation 

 or dependence ; or that a rotation round a common centre of 

 gravity has been in progress daring any part of the last 70 

 years. It is probable, therefore, that their proximity is merely 

 in appearance, and is the effect of projection ; and that, con- 

 sequently, there is no liability of the one being eclipsed by the 

 other. It is possible that this conclusion may at some future 

 period be modified ; but it is abundantly sufficient for the pre- 

 sent purpose, which is to show what was the apparent state of 

 the star at the period of M. Mdchain's observations. 



Admitting this conclusion, the fact stated by M. Flaugergues 

 involves the supposition that the smaller star must have 

 quitted the position, relative to the other, in which it had been 

 stationary for nearly 30 years, so as to be eclipsed in 1787 ; 

 and subsequently, by a motion equally rapid and in a contrary 

 direction, resumed its former position, in which it has since 

 remained stationary, for nearly 30 years more. It appears 

 difficult to reconcile such a movement of rotation with our 

 present views of the motions of the celestial bodies, and the 

 regularity of the laws which govern them. Quitting, how- 



