BOOK  III.
The  Measure  of  Gravitation
at  the  Polar  Circle.
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CHAP.  I.
Of  Gravitation  in  general.
VHATEVER  be  the  Cauſe  of  Gravitation, ¬
  we  may  conceive  it  as  a
Force  inherent  in  Bodies,  whereby  they  are
animated,  as  it  were,  and  urged  to  fall  towards ¬
  the  Earth;  and  upon  comparing  the
Effects  of  this  Force,  when  it  makes  a  Stone
fall  to  the  ground,  with  what  it  muſt  be  to
keep  the  Moon  in  her  Orbit,  we  ſhall  find
by  Calculation,  that  the  Gravitation  which
acts  here  upon  the  Earth,  extends  to  the  Region ¬
  of  the  Moon,  and  regulates  her  Motion.
As  the  Power  which  makes  Bodies  fall
downwards,  likewise  retains  the  Moon  in
her
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