THE LAW OF EQUILIBRIUM 145 



hypothenuse, hence can be going only about 8.5 miles per 

 second. This is true enough, but considering the twa 

 velocities separately and then adding, which I under- 

 stand to be the practice of astronomers, the total comes to 

 11.8 miles. In any case, the net result is so close to that 

 obtained by the laborious practical methods that either 

 result might fairly be cited in corroboration of the other. 

 Besides, it ought not to be presumed that we have ex- 

 hausted all the possible motions of the sun, and some 

 margin should be allowed for future developments. 



According to Newcomb, the pole moves 20" per 

 annum on the scroll of the celestial sphere. Taking the 

 sun's annual movement of 186,000,000 miles as the base 

 line, the question arises as to how distant the Vertex 

 must be to possess this parallax, or in other words, to 

 make the distance 186,000,000 miles subtend an angle of 

 only 20 seconds. To ascertain this we need simply divide 

 the 186,000,000 by 20 and multiply the quotient by the 

 number of seconds in a radian, yielding as a result, 1,918,- 

 000,000,000 miles, which is precisely the same value we 

 found by the other process. 



Again, it may be interposed that if, indeed, the 

 system be falling at the rate specified, it would in the pre- 

 cessional period fall a sheer height equivalent to the full 

 length of the sun's orbit practically twice as low as the 

 Vertex. This deduction, also, is right, if one remembers 

 that he is speaking only of absolute space. But the ver- 

 tex is no more riveted to one spot than a horse drawing a 

 vehicle. It is merely the crossing place of gravitational 

 strands that, real and powerful though they are, are yet 

 as imponderable, as elusive, as mobile as the rays of 

 light itself. The Vertex, in fine, is a will-o'-the-wisp, 

 beckoning the system on and on forever, and, indeed, the 

 Gravisphere itself should be conceived of as in the pro- 

 cess of falling. 



If the reader has acquired the impression that I 

 identify the vertex with the center of the stellar universe, 

 he is mistaken. There may be such a center, perhaps; 

 but if so, it is as shifting as the clouds, since all things are 

 in motion. The Vertex is for the system a proximate cen- 



