Chase.] . OoU [Nov. 4, 



112. Motion of the Solar System. 

 If the interstellar paraboloid (Note 46) were at rest, we slionld have rj 

 = 2 S; it is, however, equivalent to 5.975|^. I can think of no other reason 

 for this increase than tlie absolute motion of the system in space. If the 

 space traversed in a quarter of a solar rotation (6.377 days) is similarly in- 

 creased we have 



or i : 1.00877 : : r, : 6.05264r<, 



365 256 

 This would give, for the space traversed in a year, ^ nn„ x 6.05264ro. 



Dividing by 214.45, we obtain 1.6166 times Earth's semi-axis major. Her- 

 schel's estimate of the annual motion* is 1.623 semi-axes. 



113. Relation between Jupiter's Mass and Distance. 



Tlie original tendency to relative stability in the positions of the two 

 principal masses of our system, on account of the magnitude of Sun and the 

 nebular-centrality of Jupiter, appears to have made Sun's surface the 

 rupturing locus (secular-perihelion), of the centre of gravity of the two 

 bodies. Stockwell gives, for Jupiter's maximum eccentricity, .0608274 ; 

 secular perihelion is, therefore, .9391726 of the semi-axis major. If we 

 accept Bessel's mass, we find 1047.879 -f- .9391726 = 1115.75r„. Dividing 

 by 5.202798, we find, for Earth's semi-axis major, 214.45ro, which is the 

 value adopted in the British Nautical Almanac. 



114. The Central Sun. 



The true culminating abscissa of the stellar-solar paraboloid (Note 46), 

 is A38 = LM -=- r„. There is a very large possible uncertainty in the dis- 

 tance of a GentauH, and even if we take the most recent and careful esti- 

 mates we may set down the probable error as at least ±.04. Moreover, 

 as the theoretical variability of the abscissas is principally due to varia- 

 hility of gethereal density, A39 may represent any point in the orbit of a 

 Centauri about the centre of its stellar system. The mean R. A. of a 

 Centauriis about 217^53' and its declination 60O21'S; the opposite pole of 

 the paraboloid, or the theoretical direction of the " Central Sun," if our 

 Sun has been projected from a Centauri, should therefore be in the con- 

 stellation Cassiopeia. The direction of Sun's apparent motion among the 

 fixed stars has been variously estimated between R. A. 252^53' and 261^22', 

 and between N. Dec. 38037', and 14026'. Struve's result, from an elabo- 

 rate discussion of the proper motions of 392 stars, was R. A. 261^22', Dec. 

 37036', for A. D. 1790. This position is 4^51' north of the great circle 

 which is at right angles with the axis of the Centaurean paraboloid. 



* Outlines of Astronomy, Sect. 858. 



