THE SUN'S MOTION IN SPACE. 191 



(97) Harzer, 189S. — In 1893 Harzer criticised the mathematical 

 features of Kobold's investigation, last mentioned, and denned 

 the analytic conditions which should, in his opinion, determine 

 Kobold's solution. 1 



(98) Bisteen, 1898 (June) — Risteen, using Vogel's list of 51 stars 

 with the exception of 9 which he thought ought, for various 

 reasons, to be excluded as likely to vitiate the result, deduced 

 from the remaining 42 stars 2 



R.A.= 218-°0, D.= +45-°0, V. = 10-9 English statute miles persec. 



(99) Kobold, 189 If. — On 4th June 1894, an investigation by 

 Kobold of the proper motions of the Auwers-Bradley Catalogue, 

 according to the Besselian method, was received by the Imperial 

 Leopold-Caroline German Academy of Scientific Investigators, 

 and published in 1895. 3 This contains the places of the 3,268 

 stars previously mentioned for the epoch 1810*0, and their proper 

 motions; the latter being determined for the interval 1755 - 1865, 

 the mean of which is the epoch referred to. From the 3,268 stars 

 1,408 are selected, the poles of whose motion do not shew a greater 

 uncertainty of direction than 10°5. Remarking that the relation 

 of the weights in different instances will be as follows: — 



Uncertainty of direction j . g . g 3.3 



01 Jr.M. €(9) ± ) 

 Weight 1-0 3 2 10-0 31-6 100-0 316-2 



Kobold divided these stars into six classes, the limits of uncer- 

 tainty being as hereinafter shewn. The 1,408 stars are also 

 divided into six series, following the scale of the magnitudes of 

 the proper motions, viz., 

 Series ... A B C D E F 



Proper motion <d'l 0-1 -0-2 0-2 -04 : 4 - 0-8 0-8 -1-6 >1% 

 No. of Stars... 618 474 210 81 17 8 



1 Bemerkung zu Herrn Kobold's Aufsatz " Ueber die Bestimmung der 

 eigenen Bewegung des Sonnensystems." — Astr. Nach., Bd. cxxxiii., pp. 

 79 - 82, 1893. 



2 Astr. Journ. Vol. xin., pp. 74-75, 1893, also The Observatory, Vol. xvi., 

 p. 274, 1893. 



3 Untersuchung der Eigenbewegungen des Auwers-Bradley-Catalogs 

 nach der BessePschen Methode. — Nova Acta d. k. Leop. Carol. Deutsoh. 

 Akad. d. Naturforscher, Bd. lxiv., No. 5, pp. 215-368, 1895. 



