(2.)  The  force  dae  to  the  free  magnetism,
which  appears  at  the  surface  of  the  gap  or  cut.
The  force  on  the  unit  pole  is  compounded  of
these  two  separate  forces,  and  is  called  the  magnetic
induction  of  the  space.  Magnetic  induction  is,
therefore,  strictly  speaking,  a  quantity.
The  direction  of  magnetic  force  and  the  mag-
netic induction  are  the  same  in  an  air  space  out-
side a  magnet.  Within  a  bar  of  iron  or  other
paramagnetic  material,  under  induction  in  a  mag-
netic field,  the  magnetic  force  at  any  point  is  due
not  only  to  the  external  or  original  field,  but  also
to  the  field  produced  by  the  polarity  induced,
which  acts  opposed  to  the  magnetic  force  at
points.  Magnetic  force  and  magnetic  induction
are  identical  only  where  there  is  no  magnetism.—
{Fleming.)

When  a  magnetizable  body  is  brought  into  a
magnetic  field  the  following  phenomena  occur,
viz.:

(i.)  The  lines  of  magnetic  force  pass  through
the  body  and  are  condensed  upon  it.  (See  Field,
Magnetic.  Paramagnetic. )

(2.)  If  the  body  is  free  to  move  around  an  axis,
but  is  not  free  to  move  bodily  towards  the  magnet
pole,  it  will  come  to  rest  with  its  greatest  extent
or  length  in  the  direction  ol  the  lines  of  force;
*'.  e.,  in  the  direction  in  which  it  will  offer  the
least  resistance  to  the  lines  oJ  force  that  thread
through  it.
