THE LAW OF EQUILIBRIUM 147 



Inasmuch as the stellar motions are by astronomical 

 practice and necessity referred to the center of the sun, 

 and that in turn to the vernal equinox, we do not need to 

 confuse ourselves by attempting to combine in our 

 thoughts the earth 's annual motion of revolution with the 

 stellar motion. We can, instead, more easily and satis- 

 factorily imagine the earth as always in vernal equinox, 

 that is, sailing straight ahead of the sun on his orbital 

 path. The patient student, who will expend the necessary 

 effort in acquiring a knowledge of the methods and re- 

 sults of practical astronomers along this line, will have 

 reason to marvel at their perseverance and accuracy 

 when he finds how remarkably they are corroborated by 

 the logical deductions flowing from these theories. 



