THE SUN'S MOTION IN SPACE. 165 



(42) Fleury, 1852} — In 1852, Fleury indicated what he believed 

 to be a suitable experimental method for determining the amount 

 of motion of the solar system. 



(43) Plana, 1852. 2 — Plana, discussing in the Astronomische 

 Nachrichten of 1852, Galloway's results, gave as the result from 

 81 stars, computed by stricter methods, 



R.A. = 260-°2, D.= +36°-9 

 Epoch 1790. In his solution he applied the method of least squares 

 and discussed Galloway's solution at same length. 



(44) Struve, F. G. W., von, 1853?— The first volume of the 

 collection of Memoirs (1852 or 1853) of the Pulkova Observatory 

 contains one by Fried rich Struve on " Results relating to the 

 proper motion of the Solar System." 



(45) Arago, 1855? — Arago, in his popular astronomy, refers at 

 some length bo the work done by different astronomers, on the 

 computation of the sun's path in space ; he however contributes 

 nothing original, and as a bibliography his chapter is incomplete. 



(46) Mddler, 1856? — In 1856 Madler made a second and 

 much more thorough determination based on the proper motions 

 of no less than 2,163 stars. This gave — 



R.A. = 261-°6, D.= +39-°9 

 for the direction of the sun's motion, a direction which it has 

 since been shewn is probably the prevailing one for several stars 

 near our system. 6 



(47) Airy, 1859. — In March 1859, Airy also investigated the 

 question under discussion. 7 Pointing out what he conceived to be 



1 Methode experimentale propre a determiner le mouvement absolu de 

 Soleil.— Cherbourg. Mem. Soc. Sci. I., 1852, pp. 336. 



2 Memoire sur la direction probable que Mr. T. Galloway assigne au 

 mouvement propre du systeme solaire, etc. — Astr. Nachr. xxxrv., 1852, 

 pp. 301 - 326. 



3 Resultats relatifs . . an mouvement propre du systeme solaire. — 

 Poulkova, Recueil de Mem. i., 1852 or 1853. 



4 Mouvements propres des etoiles et translation du systeme solaire. — 

 Astronomie populaire n., 1855, p. 19. 



5 Determination de la direction suivant la quelle se meut le systeme 

 solaire. — Dorpat, Beob. xiv., 1856, p. 223. 



6 See Klinkerfues, 1878, hereinafter. 



7 On the movement of the Solar system in Space. — Monthly Notices, 

 Roy. Astr. Soc, Vol. xix., pp. 175-180, 1859. See also Memoirs, Vol 

 xxviii., pp. 143 - 172, 1860. 



