DEPARTMENT OF MERIDIAN ASTROMETRY. 



209 



in the division into giant and dwarf classifications because of the 

 difficulty in assigning a star of these types to either group. A separate 

 solution of the 72 stars of these types placed the solar apex at right- 

 ascension 262°, declination +35°, and furnished a value of 14 km. for 

 the solar velocity. 



The determination of the principal axes of the velocity figure for 

 the different divisions is given in the table. 



The velocity figure for the giant stars is less flattened at the pole 

 toward the pole of the Galaxy than that of the dwarf stars. The same 

 difference also exists between the stars of smaller space velocity com- 

 pared with the stars of large velocity. The position of the vertex of 

 preferential motion for the large-velocity stars, taken with the peculiar 

 distribution of the motions of these stars, accounts for the shift in the 

 position of the sun's apex as derived from them. The velocity figure 

 of the A and B stars proved not only exceedingly flat in the direction 

 of the pole of the Galaxy, but the secondary axis is also small, being 

 but half the size of the principal axis. 



Grouping the stars according to type and separating the t>T)es in 

 turn into giant and dwarf classifications, it is found that the space 

 velocity both for giants and dwarfs increases with progression in type 

 from B to M types. The increase of the velocity with progression in 

 type was unexpected in the case of the giant stars and is somewhat hard 

 to explain according to the more generally accepted theories regarding 

 stellar evolution. When the stars were grouped according to divisions 

 in absolute magnitude it developed that the velocity increased with 

 decreasing intrinsic brightness of the star. The space veloci'^^y of the 

 star seems to be a linear function of its absolute magnitude. 



Five possible groups of stars were picked out, two of them the known 

 ones of Taurus and Ursa Major. The apex of the Taurus group was 

 placed at right-ascension 96°, declination +33°, with a group velocity 

 of 29 km. The apex of the Ursa Major group was placed at right- 

 ascension 282°, dechnation +2°, with a group velocity of 32 km. 

 A very real-appearing group was located with an apex at right-ascen- 

 sion 100°, declination +22°, and a group velocity of 30 km. Two 

 other possible groups were found, the first with an apex at right ascen- 

 sion 97°, declination +12°, with a group velocity of 73 km., and the 



