28 FROM NEBULA TO NEBULA 



Finding 1 itself originally out of balance with the uni- 

 verse at large, it first toppled and then tumbled, and 

 it is still tumbling, with ever accelerating velocity, down 

 the abyss of space, and will continue to do so until 

 it shall find, or unless it shall find, a place to alight. 

 Why the planets started to turn eastward instead of 

 westward was as much a pure matter of chance as 

 how our pole was to fall the slightest cause might have 

 sufficed. Once the die was cast, however, it was cast for 

 every body in the system, and all had to follow their 

 leader along the course marked out for them by the 

 rival force's of the sun on the one hand and the Prime 

 Resultant on the other. An endless diagonal line of 

 force and movement resulted for each member of the 

 system. Down spiral stairways they descend, attended 

 by the sun and by each other, mutually sustaining one 

 another as they go, in perfect equipoise,, A SYMBOL OF 



ANYTHING BUT CHANCE AND GUESS. 



We have already seen how Newton arrived at the 

 law of gravitation by testing its virtue at the touch- 

 stone of Kepler's laws. But whereas he tested the truth 

 of that principle from within, it is for us now to test the 

 truth of it, BY THE SAME TOUCHSTONE, from without. 

 He proved, once and for all, that the centripetal force 

 that tethers the planets to their orbits is the same as 

 that which causes the apple to fall. If it be equally 

 true that the centrifugal motion is due to an external 

 source of gravitational attraction, then we ought to be 

 able to prove the fact by some means as simple and 

 convincing as Newton proved his part. 



No\v, weight is our test of the force of gravity 

 the balance-scale is the instrument for testing weights 

 and THE LEVER is the mechanical principle governing 

 the balance. If it be true then ttiat the solar svstem 



