Vital Physics. 47 



of their orbits. Again, page 81, Ibid : "The first law of 

 motion is simply this, If a body be once set in motion, and 

 if it have a certain velocity given to it, it will continue to 

 move (if not acted upon by another force) in a straight 

 line with unabated velocity. Hence, the law of motion 

 by the tangent is the first or starting law of motion for 

 the earth and planets in running along the course of their 

 orbits." 



By this very law of motion the axoidal motion would be 

 in the reverse order of direction to that in which it is found. 

 It is asked, But does not this go against the attractive force 

 being the only force? Certainly, but in explaining the 

 orbital motion the axoidal motion is never referred to, as 

 though the two motions had no relation to each other, though 

 effected by one and the same force. This absence of explana- 

 tion is the more mysterious, as the axoidal motion is often 

 referred to in works of astronomy, and is a matter universally 

 examined by all practical observers. 



Can anything be proposed as an off-set, supposing the 

 tangental is only admitted as a qualifying agent in account- 

 ing for both orbital and axoidal motion? Here a suggestion, 

 rather than a demonstration, is given without further 

 apology. Let it be supposed that there are two forces of 

 unequal acceleration ; or, to put it in other words, that one 

 obeys the law of intension in inverse ratio to the square of 

 the distance, and the other, which is the weaker of the two, 

 diminishes in the degree of acceleration more slowly than that 

 of inverse ratio to the square of the distance, and in pro- 

 portion to the mass. 



This ratio of diminution requires a little explanation. 

 Then let it be said that a force called attraction dimi- 

 nishes in intensity of force as it recedes from the focus 

 of action in a fixed and constant manner, and also in 

 a very rapid manner ; but a force, here called the 



