Accordingly,  in  creating  futm-e  freeholds  at  common
law,  the  following  rule  must  be  remembered : — A  fi(fure
free/iold  inferest  must  he  limited  to  commence  imnicdiateJy  on
the  determination  of  a  precedent  freehold  interest,  and  if  it  be
limited  to  commence  on  any  other  event  or  contingency,  the
limitation  is  void  from  its  inception.     (5  Rep.  94  b.)

Freeholds  limited  to  commence  on  any  other  event  than


124  MODES  OF  llOLDINC;  INTEUESTS.
the  dotorniiuatiou  of  a  prior  froohold  arosaid  to  bo  liniitod
ill  /i(fiiro.
Eule  of  Construction. — TUo  old  dootriuo  of  the  ooiumon
law,  that  ovorv  froohold  iiitorost  in  laud,  whothor  in  posses-
sion or  expeotauoy,  nmst  at  its  inooi'tiou  have  a  certain
and  existing-  owner,  led  to  the  establisluuent  of  a  rule
of  eonstruetion,  whieh  still  applies  to  all  liiuitations  of
freeholds,  wliothev  at  eonuuou  law,  by  will,  or  by  way
of  use.  That  rule  is  called  the  Iiuic  in  ^7/('//<7/^^•  Ci/si',  from
its  being"  reported  in  a  fanunis  ease  of  that  luinie  in
Lord  Coke's  Ixeports.  It  will  be  best  explained  by  an
example.
