250 Mr. South's observations of the apparent distances 



No. DCCXLI. continued. "-'^-'^ ' 

 Mean Result. 

 of A. B. Position 86° 13' nf (10 Obs.) ; Epoch 1825.59 ; 



Distance 6".^S9 (20 Obs.) ; Epoch 1825.64. 



of AC. Position 60° 12' 5/(10 Obs.); Epoch 1825.62 ; 



Distance 57*.325 (i5 Obs.) ; Epoch 1 835.^5- 



No. DCCXLII. R. A. 20^^ 8- ; Decl. 46« 12' N. 



0^ Cygni ; Struve, 667 ; VI. 10. 



Double ; 5th and 8th magnitudes. 



Blackman-street ; June 28, 1824 ; Five-feet Equatorial. 



Position = 840 o' sf 

 Distances: i'46".376 



5 Obs. I DifF. = o<> 15' ) 

 5 Obs. I Diff. = i".o42> 



Observed when 4 hours east of the meridian. 



Passy; November 3, 1824 ; Seven-feet Equatorial. 

 5 th and 8th magnitudes. 



Position =83° 47' sf 

 Distance = i' 46".4io 



5 Obs. I Ditf. = 0° 35' ) 



5 Obs. J DifF. = I ".250 



Mean Result. 

 Position 8s° 5s* sj; Distance 1' 46".393 ; Epoch 1824.66. 



The position of 1781 is 87° 14' sp, differing 8° 53' from 

 the present ; an extraordinary change for a star of the 6th 

 class, and one so easy of measurement. In Piazzi's cata- 

 logue, a proper motion of — o".03 in R. A. and +o''.i8 in 

 declination is ascribed to the large star. This should carry 

 the large star almost directly away from the small one (and 

 indeed there is an apparent increase of 6" in the distance, 

 could the earlier measure be relied on) ; but no sensible 

 change of angle could thus arise. This star should be re- 

 measured after a lapse of 20 or 30 years. (H.) 



