GREAT REFRACTING TELESCOPE AT ELCHIES, IN MORAYSHIRE. 



381 



Part B. — Observational Particulars. 35 PISCIUM — continued. 



Com- Magni- Colour. Position. Distance. Date. Authority, 



ponents. tude. ■' 



A 6 Pale white „ ^ „ 



B 8 Violet tint AB 149 30(t(;7) ll-90(ti;7) 1837-89 Cycle. 



A 

 B 



A 

 B 



A 

 B 



A 

 B 



Yellowish 

 Azure 



White..., 

 Purplish 



Yellowish(2) 

 Pale violet (2), 



1844-8 



Sestini. 



6 (3) Yellowish \vhite(3) 



8 (3) Greyish (3) AB 14949*(w2) ll-64(wl) 



1850-7 Spec. Hart. 



1856-68 AltaVista. 



1862-72 Elchies. 



Mean of four best results, 1832-1838 ; position AB 149° 42'; distance ll"-60; date 1834-84. 

 Elchies corrected for constant differences; position AB 149° 41'; distance ll"-67 ; date 1862-72. 



When the results of different observers are arranged in this clear and tabular 

 manner, it seems, at first sight, so extremely easy to judge by mere inspection, 

 whether our knowledge of the star is in a satisfactory condition or otherwise, 

 that it is needless to add anything to them. Yet a very little further examina- 

 tion will soon reveal, that there are a great many unknown quantities to be taken 

 into account, and that it is often extremely difficult to come to a decision between 

 what shall be attributed to error of observation in a former observer, and what to 

 a real change in the star or star-group itself; and, according as the decision 

 may be given one way or the other, so the new" Elchies observation may fulfil a 

 more or less useful part in the history of the star. At all events, it is only 

 by such a comparison, rigidly, impartially, and extensively carried out, that 

 we can really arrive at any definite idea, as to whether the Elchies observations 

 are in themselves good or bad, (merely to have printed them by themselves, 

 would have proved nothing), and whether they have haply added anything to 



* The numbers in simple parenthesis after an Elchies observation, indicate the number of 

 nights on which it was observed in any particular element ; but when a w is prefixed to the number, 

 it indicates the estimated weight concluded on the principles mentioned in page 376. The original 

 authorities referred to for numerical observations, are, — 



" Mensurse Micrometricse" of F. G. W. von Struve, quoted as 2, when observing with the 9-inch, 



and g, with the 3*6-inch Dorpat Equatorial. 

 " Cape of Good Hope Observations," by Sir J. F. W. Herschel, quoted as H^. 

 '« Cycle," by Admiral W. H. Smyth, 1844. 

 '' Speculum Hartwellianum," by the same, 1860. 



Memoirs and Monthly Proceedings of Royal Astronomical Society ; Astronomisches, Nachrichten, 

 by Dr A. Auvers ; and Edinburgh Astronomical Observations, vol. xii., for Guajara and 

 Alta Vista observations in TenerifFe. Other references to Sir William Herschel, as H^, and 

 Sir John Herschel and Sir James South, as H^ and S, are extracted either from the " Men- 

 suras Micrometricse," or the " Cycle " 



