The  copper  is  found  usually  both  in  the  pickles  and  m  the  vinegar ;
and  for  its  detection  the  following  processes  may  be  adopted : —

For  its  detection  in  pickling  vinegar,  an  ounce  or  so  of  the  vinegar
should  be  poured  into  a  test  glass,  and  in  this  a  piece  of  thick  iron
wire,  having  a  smooth  and  polished  surface,  should  be  immersed  for  a
few  hours.  If  copper  be  present  it  will  become  deposited  upon  the
wire,  forming  a  coating  more  or  less  complete  and  thick,  according  to
the  quantity  of  copper  present.
This  test  may  be  so  readily  applied  that  we  recommend  the  public
to  make  use  of  it,  and  so  ascertain  for  themselves  whether  the  pickles
they  are  using  contain  the  poison  or  not.  If  only  a  very  small  quan-
tity of  copper  be  present  it  will  be  quickly  deposited  on  the  surface
of  the  iron.
POISONOUS   BOTTLED   FRUITS   AND   VEGETABLES.     409

We  have  ourselves  tried  this  simple  proceeding,  first  with  half  an
ounce  of  two  vinegars  in  which  the  pickles  were  contained,  in  which
much  copper  was  present ;  in  each  case,  after  the  lapse  of  three  or
four  hours,  a  well-marked  coating  of  copper  had  formed  upon  the  iron
rod.  We  next  tried  it  with  two  vinegars  previously  ascertained  to
contain  the  smallest  quantity  of  copper ;  in  these  cases  also,  after
the  lapse  of  a  few  hours,  an  incrustation  of  copper  was  formed.
