THE SUN'S MOTION IN SPACE. 203 



T= 7T v/{(Rad. Earth x Density Earth)/ 



(Accel. Gravity x Density Aether) j 



(120) Bakhuyzen, 1897 (Dec.) — The question of the distribution 

 of stars in space, is a fundamentally important question in complete 

 methods of determining the solar motion : recognising this, Van de 

 Sande Bakhuyzen 1 in 1898 undertook the investigation of the 

 number of proper motions to be expected within definite limits, 

 assuming any definite elements for the sun's motion, He adopted 

 Ludwig Struve's values for the year 1875, viz., 



R.A. = 276°, D.= +34°. 



His fundamental hypotheses are (a) that the motus peculiares 

 of the stars vary between very wide limits, and spatially are dis- 

 tributed accidentally, i.e., both in respect of quantity and direction: 

 (b) that the proportion of stars with motus peculiares lying between 

 any definite limits, and included between the surfaces of concentric 

 spheres, is independent of their radii: and (c) that the mean 

 velocity in such a case is also independent of the radii. 2,683 

 stars were found to be distributed substantially as required by the 

 hypothesis. 



(121) Boss, 1898 (Jan.) — Boss 2 — in a further discussion on 

 Newcomb's value for the precessional constant, roughly revising 

 Ristenpart's equations, allowing for Becker's personal equation 

 for star magnitude, adjusting to the system of the principal stars 

 of the American Ephemeris, and so combining the equations that 

 the solar-apex coordinates shall depend upon 454 stars having 

 apparent proper motion greater than 0""1, while the correction to 

 the Struve-Peters \j/ shall be derived from the remaining 4,565 

 stars — found for the apex of solar motion, the value 



R.A. = 295-°4, D.= +39-°0 



1 Opmerkingen over de verdeeling der sterren in de ruimte. — Yerslagen 

 d. Afd. Natuurk. Dl 6, 1897-8, pp. 394 - 404. See also Astr. Nach., Bd. 

 cxlvi., pp. 209 - 220, 1898, in which to the title is added, " nach der 

 Grosse der Eigenbewegungen." 



2 The Paris Conference and the precessional motion. — Astr. Journ., Vol. 

 xviii., (No. 423) pp. 113 - 118, 1898. 3 Loc. tit, p. 117. 



