384 



PROFESSOR C. PIAZZI SMYTH ON THE 



65 'PISCIUM— continued. 



Com- Magni- ^.^j^^^ Position. Distance, 



ponents. tude. 



A 6 Pale yellow ^ ^ „ 



B 7 Paleyellow AB298 12(w6) 4-2(w4) 



A 

 B 



A 

 B 



A 

 B 



A 

 B 



A 

 B 



A 

 B 



6-0 Yellowisli 



62 Yellowish AB 298 58 



4-45 



AB298 30 (w 8) 45 (it; 5) 



Yellowish 

 Azure 



Pale yellow 

 Pale yellow 



White (1) 

 White (1) 



Date. Authority. 



1830-97 Cycle. 



1832-13 2. 



183817 Cycle. 



1844-8 Sestini. 



1850-8 Spec. Hart. 



1856-68 AltaVista. 



6-3 Bluish white (2) 



7-0 Faint yellowish white (2) AB 298 28 (i</2) 



4-55 (t«l) 1862-73 Elchies. 



Meanof 3 best obs. 1830-39, Pos. = 298°33' Dist. = 4"-38 Date=1833-72. 



Elchies corrected, Pos. = 298°20' Dist. = 4"-58 Date = 1862-73. 



In Magnitude, these stars seem steady. 



In Colour, they are weak, but may be slightly variable interchangeably. 



In Position and Distance, they are a remarkable lesson ; for whereas the first 

 three sets of measures showed a change of 5^" of position in forty years, on 

 the strength of which an orbit was computed of one star round the other in 

 3000 years,— subsequent measures have proved that there was no sensible change 

 at all, and the appearance of it was merely due to the large errors of observation 

 of the earliest authorities, and to their chancing to tend in one direction. If 

 further proof of the " fixity" were needed, it is supplied, as will be seen, by the 

 Elchies observations. 



In Character the stars may still be termed physical, or slow binaries, by the 

 entire non-appearance of the B. A. C. proper motion, which, on the optical hypo- 

 thesis, ought to have decreased the position by 17°, and increased the distance 

 by VT' in thirty years. 



(3.) ^}.' PISCIUM, Approx. R.A. 0^ 58"° 17^; Decl. + 20° 44' 1", January 1, 1862. 



uonents tude Colour. Position. Distance. Date. Authority. 



A 



B ... AB 170 27-50 1779-83 H^. 



A 4-7 



B 5-2 AB 161 30-04 1821-93 a. 



