ASTRONOMICAL  ESSAYS.
20
the  standard  path,  or  orbit.  Astronomers  generally ¬
  assume  the  earth's  orbit,  as  the  standard
from  which  to  compute  the  inclination  of  the
others,  and  call  it  the  ECLIPTIC.  The  points
where  the  orbits  intersect  each  other,  are  called
the  NODES.
The  inclination  of  the  orbits  to  each  other,
may  be  rendered  more  familiar  to  the  imagination,* ¬
  by  taking  as  many  hoops  as  there  are
planets,  with  a  wire  thrust  through  each,  and
thereby  joined  to  that  hoop  which  represents  the
ecliptic;  the  other  hoops  may  be  then  set  more
or  less  obliquely,  to  the  representative  of  the
ecliptic.
The  several  orbits  do  not  cross  or  intersect  the
ecliptic  in  the  same  point,  or  at  the  same  angles;
but  their  nodes,  or  intersections,  are  at  different
parts  of  the  ecliptic.
It  ſhould,  however,  be  observed  here,  that  in
speaking  of  the  orbits  of  the  planets,  nothing
more  is  meant  by  this  term,  than  the  paths  they
paſs  through  in  the  open  ſpace  in  which  they
move,  and  in  which  they  are  retained  by  a  celestial ¬
  but  continuous  mechanism.
Or
*  Dr.  Watts’s  Astronomy.