avoid  the  rights  of  parties  (m).  A  material  alteration  is  one
which  affects  the  contract  or  any  rights  or  remedies  under  it ;
or  which  affects  the  use  of  the  instrument  for  its  proper  pur-
pose (o)  :  as  an  alteration  in  a  sale  note  of  goods  by  the
seller  adding  a  stipulation,  that  damaged  goods  should  be
taken  at  an  allowance  by  valuation  (p) ;  or  by  the  buyer
adding  to  a  sale  of  goods  "  by  sample  "  the  words  "  of  their
own  manufacture,"  such  alteration  being  material  whether
the  words  referred  to  the  bulk  of  the  goods,  or  to  the  sample
only  (q)  ;  an  alteration  of  a  written  contract  by  adding  a  seal
to  the  signature  so  as  to  make  it  appear  to  be  a  contract  under
seal  (r).  A  deed  of  composition  between  a  debtor  and  the
creditors  named  in  the  schedule  was  held  to  be  materially
altered  by  the  addition  of  the  schedule  after  execution  (s).
But  a  like  deed,  pm-porting  to  include  as  parties  aU  the
creditors,  and  duly  executed  by  a  majority  sufficient  to  bind
all,  was  held  not  to  be  materially  altered  by  the  addition  of
names  of  creditors  in  the  schedule  as  the  addition  was  within
the  terms  of  the  deed  (t).  In  policies  of  insurance,  an  altera-
tion by  inserting  a  new  subject  of  insurance  (ti) ;  or  by  altering
the  time  of  sailing  warranted  (,r)  ;  or  by  altering  the  port  of

{k)    Wilkinson  v.  Johnson,  3  B.   &  (p)  Powell  r.  Divett,  15  East,  29.
C.  428.  (<?)  Mollett  y.  Wacl-erbarth,  5  C.  B,

(t)  Saper  v.  Birkbeclc,  15  East,  17  ;  181.
