44 Vital Physics. 



and decrease of acceleration, as it nears or recedes from the 

 perihelion, is simply a law of motion based upon the direction 

 in which the planet goes, if its course is in an ellipsis ; for if 

 it were moving in a perfect circle increase of acceleration 

 would not exist, but the radius vector (drawn from the sun to 

 the planet) would not only sweep over equal areas in equal 

 times, but equal areas would extend over equal distances 

 in the line of the orbit in like times, and that without the 

 slightest variation of time in traversing the line of the orbit 

 throughout all parts of its course. This part of orbital 

 motion is therefore freely admitted, and if not it does not 

 matter, for observation proves it, whether admitted or denied ; 

 but the subject of inertia, as applied to tangental motion, 

 is rejected on other grounds. 



Inertia is complete passiveness ; so that a motion started 

 in a straight line continues in a straight line, ad infinitum, 

 if unchecked or uncounterpoised, and this passiveness resides 

 in all matter. Now, if motion in one direction is checked 

 by that of an opposite, we certainly get the diagonal or 

 resultant of the two, but we do not get inertia active to 

 resist the continued central force which gains by being 

 neared ; and it is admitted that in one direction it has already 

 given way to the diagonal, and in the diagonal direction it 

 must again succumb in like manner from mere passiveness, 

 and far from falling off from the circumference of the orbit 

 it must be getting nearer the centre, according to the law of 

 inertia. 



Secondly, matter as inert cannot move in two different 

 directions ; it must go in one direction or another, not in two 

 at one and the same time. Therefore, as the matter of this 

 earth is at all times moving in a circle, by revolving round 

 its own axis, every particle of matter in the globe is changing 

 every minute in the direction of its tangent ; therefore, 

 it follows that it is impossible for the matter of the 



