6  C.  P.  523,  gives  a  number  of
tests  which  may  be  apphed  with
practical  results  in  determining
this  question  at  page  529 :

"If  two  persons  undertake
jointly  to  write  a  play,  agreeing
on  the  general  outline  and  design
and  sharing  the  labor  of  working
it  out,  each  would  bo  contribut-
ing to  the  whole  production  and
they  might  be  said  to  be  joint
authors  of  it,  but  to  constitute  a
joint  authorship  there  must  be
a  common  design."  And  again
at  page  530:

"But  I  take  it  that  if  two  per-
sons agree  to  write  a  piece,  there
being  an  original  joint  design
and  the  co-operation  of  the  two
in  carrying  out  that  joint  design,
there  can  be  no  didiculty  in
saying  they  are  joint  authors  of
the  work  though  one  may  do  a
larger  share  than  the  other."

This  case  has  been  cited  with


approval  and  followed  in  the
state  and  federal  courts  of  this
country.
The  latest  decision  defining
what  constitutes  co-authorship  is
Maurel  v.  Smith  (1915),  220  Fed.
(D.  C.)  195.
It  was  held  that  the  plaintiff
who  wrote  the  scenario,  the  de-
fendant Harry  B.  Smith  who
composed  the  libretto  and  the
defendant  Robert  B.  Smith  who
composed  the  lyrics  of  an  operetta
were  co-authors.
Tree  v.  Boivkett  (Eng.)  (1896),
77  L.  T.  77.  It  was  held  in  this
case  that  the  adaptor  of  a  play
who  introduced  into  his  version
material  alteration  was  an  "au-
thor of  a  dramatic  piece"  within
the  dramatic  Copyright  Act  of
1833.
For  cases  where  a  co-worker
was  held  not  to  be  a  co-author
see:  Peters  v.  Bnrf<t  (1889),  9
N.  Y.  Supp.  789;  rovorscd  in  142
N.  Y.  62;  36  N.  K.  814,  upon  an-
other ground.
