164 G. H. KNIBBS. 



(40) Galloway, 18Jf7. — On the year following the appearance 

 of Madler's memoir on a " Central Sun," Thomas Galloway, 1 secre- 

 tary of the Royal Astronomical Society, studied the solar-motion 

 problem with new material. He selected 81 stars in the southern 

 hemisphere, observed by Johnson and Henderson, comparing their 

 places with the catalogues of Lacaille and Bradley. These stars 

 had a P.M. of at least (Kl per annum, 65 depending on Lacaille 

 and 16 on Bradley's results. In respect of the principle of com- 

 puting the solar motion, Galloway argued that each equation 

 should have equal weight since we know nothing of the absolute 

 velocity of a star's motion, or of its distance. His final deduc- 

 tions, based on the assumption indicated, were : — 



81 stars, general result :— R, A. = 263*°8 D. = + 37'°3 



79 stars, re-calculated with two 



stars rejected „ 257'°1 „ 34-°3 



78 stars, re-calculated with a further 



rejection of one star , 26O°0 „ 34'°4 



The coordinates are for the epoch 1790. 



Galloway considered the possible error of the catalogues, and 

 shewed that the annual P.M. 0-"l, was greater than the probable 

 error of the catalogue. The close accord with the results of 

 Argelander and Struve he regarded as considerably enhancing the 

 probability of the conclusions reached, 



(41) Encke, 18 J/7. 2 — In an article on von Struve's study of 

 stellar astronomy, Encke discussed Gauss' representations respect- 

 ing the uncertainty of our knowledge of the direction of the sun's 

 movement. 3 Struve had, according to Encke, assigned a point in 

 the line joining the two third-magnitude stars tv and fx Herculis, 

 one-fourth of the whole distance from the former — that is a point 

 whose coordinates in 1847 would be 



R.A.=259-°3, D.= + 34-°7 

 This is obviously the result previously given, see (34). 



1 On the proper motion of the Solar System by Thomas Galloway, 

 m.a., f.b.s. — Phil. Trans. Reprint Vol. lxv., pp. 79-109, March, 1847. 



2 Ueber die " etudes d'astronomie stellaire " von Struve. — Astr. Nach. 

 xxvi., 1848, pp. 337 - 350. 



3 Gauss, Darstellung hinsichtlich der Ungewissheit in der Bestimmung 

 der Richtung der Sonnenbewegung.— Loc. cit., p. 348. 



