208

POLITICAL  ECONOMY

finished  off.  For  its  completion  we  require
a  finer  instrument  than  has  been  employed
hitherto  ;  we  must  lay  aside  the  palette  knife
and  take  up  the  brush.  The  reader  will
guess  that  by  the  finer  instrument  the
marginal  method  is  meant.  Without  the  use
of  this  method  a  complete  and  consistent
doctrine  of  rent  is  unattainable.  It  is  true
that  we  have  already  had  recourse  again  and
again  in  this  chapter  to  the  term  “  marginal,”
but  the  reader  will  not  have  failed  to  observe
that  in  every  case  marginal  quality  has
been  intended.  The  conception  of  marginal
quality  does  not  incorporate  the  fundamental
idea  of  what  is  known  as  the  marginal
method.
It  was  posited  at  the  outset  of  our  demonstration ­
  that  in  farming  every  acre  of
land,  whatever  its  quality  and  position  with
reference  to  the  market,  would  have  devoted
to  it  the  same  amount  of  capital.  Now  this
assumption,  we  all  of  us  know,  is  a  pure  fiction.
As  a  matter  of  fact  the  most  fertile  and  the
best  situated  land  will  be  worked  most  intensively, ­
  and  by  being  worked  most  intensively
we  mean  that  most  labour  and  capital
will  be  applied  to  its  cultivation  per  acre.
We  have,  then,  to  determine  how  much  labour
and  capital  will  be  devoted  to  each  plot  of