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PREPARING  SULPHATE  OF  CADMIUM. 
8s.  9d.  per  lb.  Rich  as  are  the  forests  of  Bolivia,  from  which 
the  world  draws  its  sole  supply  at  present,  they  will  not  last 
long.  Formerly  the  trees  were  every  where  found  around  the 
inhabited  parts  of  the  region,  but  now  to  meet  with  one  of  a  tole- 
rable size  it  is  necessary  to  penetrate  several  days' journey  into 
the  forest.  What  India  is  doing  as  a  substitute  for  North 
America  in  rice  and  cotton,  she  must  become  for  South  America 
as  an  exporter  of  quinia  bark.  We  believe  a  nursery  will  soon 
be  established  on  Khasai  Hills.  In  less  than  ten  years  India 
should  supply  herself  with  all  the  quinine  she  needs.  In  a  few 
more,  sulphate  of  quinine  as  well  as  quinia  bark,  should  bulk 
largely  among  her  exports.— Med.  News,  from  Friend  of  India. 
A  QUICK  AND  EASY  METHOD  OF  PREPARING  SULPHATE  OF 
CADMIUM. 
This  method,  adopted  by  the  author,  is  nothing  more  than  the 
application  of  the  fact  observed  in  1792  by  Richter,  that  a 
metal  plunged  in  a  saline  solution  substitutes  itself  for  the 
metal,  which  forms  the  base  of  the  salt  employed.  A  quantity 
of  crystallized  sulphate  of  copper,  say  100  grammes,  is  dissolved 
in  water,  and  a  piece  of  cadmium,  rather  more  than  is  necessary 
to  saturate  all  the  sulphuric  acid,  or  in  this  case  more  than  44*59 
grammes,  is  plunged  into  the  solution.  The  whole  having 
been  allowed  to  stand  for  some  time,  the  precipitated  metallic 
copper  is  then  separated  by  filtration  and  the  liquid  slowly  evapo- 
rated. If  during  evaporation  the  neutral  solution  of  sulphate  of 
cadmium  should  deposit  a  small  quantity  of  sesquioxide  of  iron, 
which  not  only  constitutes  an  impurity,  but  gives  the  salt  a  bad 
appearance,  it  is  necessary  to  expose  the  solution  to  the  atmos- 
phere until  all  the  iron  which  it  may  contain  has  been  elimi- 
nated, which  is  accomplished  when  after  a  second  filtration  the 
transparency  of  the  solution  is  no  longer  disturbed.  To  obtain 
finally  the  sulphate  of  cadmium  in  well-formed  crystals,  it  is 
necessary  to  acidulate  the  solution  slightly  with  dilute  sulphuric 
acid. — Repertoire  de  Pharm.  from  Journ.  Md.  Col.  of  Pharm. 
