76 FROM NEBULA TO NEBULA 



will fling it even more accurately than any mathematician 

 could compute its proper course, and that He could im- 

 press upon it such velocity as He listed. Moreover, 

 Newton might add, the Divinity still watches over His 

 universe and by His mere fiat can readjust it, when and 

 where needed, just as effectually as when He created it. 

 Do I hear any astronomer make like claims of conscious 

 design on the part of inanimate nature 1 (v. pp. 3, 7 ante.) 



Now, in the solar system there are eight major 

 planets, some twenty-five satellites, and more than 700 as- 

 teroids, all of whose orbits are very much larger than that 

 of the moon, and whose trajectories consequently are in- 

 finitely straighter. Are we to believe that these, too, 

 have uncaused motions, that these motions are all miracu- 

 lously tangential, and that their speeds are magically ac- 

 commodated by mere accident to the strength of their 

 several central forces'? 



Again, returning to Figure 1, suppose the moon to 

 have initially left the point with a velocity capable of 

 carrying her in one second, under the first law of motion, 

 to the point A, would she on arriving at the point P (the 

 earth's gravity having meanwhile acted) possess the 

 momentum necessary to carry her in the succeeding sec- 

 ond all the way to B ( AB being taken as equal to OA) ? 

 Most certainly not. For, as every tyro in mathematics 

 knows, any arc of any conic section is shorter than its 

 tangent, OP is therefore shorter than OA, and the moon ? s 

 velocity at P cannot possibly be as great as when she left 

 the original starting point. It matters not, therefore, 

 how accurate the initial adjustment may be hypothesized, 

 its perfection perishes in the very next moment. 



By way of an attempt to parry this difficulty, New- 

 tonians have succeeded in persuading themselves that 

 mathematical exactness between the velocity of the tan- 

 gential motion and the force of gravity is not vital to the 

 practicability of their conception. They tell us, with 

 every show of confidence in their words and manner, that 

 if the velocity bears to gravity a certain ratio, the result- 

 ing orbit will be a circle ; that if this velocity be exceeded, 



