THE SUN'S MOTION IN SPACE. 169 



the earth's annual motion appears to be verified, but the evidence 

 of solar motion was doubtful. 1 



(56) JDunkin, 1863. — In 1863 Dunkin computed the solar 

 motion from the proper motions of 1,167 stars. 2 These he 

 arranged in seven groups according to Struve's magnitude-parallax 

 theory, the distribution in right ascension being nearly uniform, 

 and about two-thirds of the stars being in the northern hemisphere. 

 The assumed relative distances, and the number of stars corres- 

 ponding to each were : 



Distance 1-0 1*71 2-57 3-76 5-44 7-86 11-34 



3 Proctor's Dist. 1-0 4-7 3-2 4-1 2-0 4-5 5-0 

 No. of Stars 9 55 146 238 330 368 21 



The results on Airy's two suppositions were — 



(a) R.A. = 261-°2, D.= +32-°9, R. = 0'"335 



(b) 263-°7 25-°0 (K410 



Dunkin remarked that probably a few stars of the fourth, fifth, 

 and sixth magnitudes with large proper motions, are after all near 

 stars, and notwithstanding that his values for the quantity of 

 solar motion were sensibly the same as Struve's, (K339, he 

 regards the fundamental assumptions as resting upon a very 

 slender basis. 



(57) Stone, 1863.— On 11th December, 1863, E. J. Stone, con- 

 tributed a discussion merely on the quantity of the solar motion. 

 Accepting R.A. = 260° N.P.D. =55°37' as the direction thereof, 

 he found, rejecting stars within 10° of the pole, from the proper 

 motions in R.A. CK434, and from those in N.P.D. CT341. The 

 mean 0'"403 would represent the motion at the mean distance of 

 the group of stars considered. Stone alleges that if Bradley's 



o o 



1 Ny bestanming af ljusets vaglangder jemte en method att pa optisk 

 vag bestamrna solsystemets progressiva rorelse. — Oefv. Vetensk. Akad. 

 Forhandl., Stockholm, Bd. xx., p. 41, 1863. See also Pogg. Annal., cxvu., 

 p. 290, and Phil. Mag. Vol. xxix., 4 Ser., 1865, pp. 489-501. 



2 Monthly Notices.— Eoy. Astr. Soc, Vol. xxiii., pp. 166 - 169. 



3 See hereinafter. 



4 On the motion of the solar system in space.— Month. Not. Eoy. Astr. 

 Soc, Vol. xxiv., pp. 36 - 39, 1864. 



