142  SOURCE  OF  SULPHUR. 
ply  have  become  available : — 1st,  Belgian  ;  2d,  Norwegian  ;  3d, 
Spanish  or  Portuguese  ;  4th,  Italian  ;  5th,  Westphalian  pyrites. 
1.  The  Belgian  pyrites  has  the  advantage  of  being  shipped  at 
Antwerp  at  a  moderate  freight  to  the  Tyne.  It  is  a  very  hard, 
compact  material,  containing  about  50  per  cent,  of  sulphur,  and 
therefore  nearly  approaches  a  pure  bi-sulphuret  of  iron.  The 
burnt  residue  from  one  manufactory  on  the  Tyne  (the  Walker 
Alkali  Works),  after  being  roasted  in  a  lime-kiln  to  burn  off  the 
small  remaining  portion  of  sulphur,  is  regularly  used  as  an  iron 
ore  at  the  adjoining  iron  works.  It  contains  no  copper,  and  from 
3  to  5  per  cent,  of  arsenic.  2.  The  Norwegian  pyrites  is  shipped 
at  Levanger.  It  contains  44  per  cent,  of  sulphur,  is  easily  broken, 
and  does  not  readily  flux  in  the  kiln.  The  quantity  of  copper  it 
contains  being  less  than  ten  per  cent.,  the  burned  residue  cannot 
be  profitably  smelted  for  copper.  3.  The  most  extensively  used 
pyrites  is  shipped  from  Huelva,  in  Spain,  and  Pomeron,  in  Por- 
tugal. The  mines  are  situated  on  each  side  of  the  boundary  be- 
tween the  two  countries.  They  were  most  extensively  worked 
in  ancient  times,  but  their  recent  development  has  arisen  from 
the  use  of  the  ore  as  a  source  of  sulphur.  Containing  only  two 
to  four  per  cent,  of  copper,  it  was  unable  to  compete  with  the 
richer  ores  which  from  time  to  time  became  available  in  different 
parts  of  the  world,  but  the  mining  is  now  rendered  profitable  by 
the  value  of  the  sulphur  being  realisable  as  well  as  tha  t  of  the 
copper.  The  percentage  of  sulphur  varies  from  46  to  50.  The 
practical  difficulty  of  burning  this  ore,  namely,  its  great  fusibility 
at  the  point  where  the  combustion  of  the  sulphur  gives  rise  to 
considerable  heat,  has  been  overcome  by  the  adoption  of  kilns, 
first  used  in  Lancashire,  in  which  the  area  of  the  surface  is  large 
in  proportion  to  the  weight  of  the  charged  pyrites.  The  use  of 
cupreous  pyrites  has  led  to  the  introduction  of  the  manufacture 
of  copper  on  the  Tyne,  which  will  this  year  amount  to  between 
700  and  800  tons.  The  ordinary  process  of  smelting  is  employed, 
— but  the  moist  method  is  also  being  tried,  the  advantage  being 
that,  by  this  method,  all  the  ingredients  of  the  mineral  are 
utilised,  the  oxide  of  iron  making  an  ore  of  similar  quality  to  he- 
matite. The  smelting  process,  however,  is  still  preferred  in  the 
large  manufactories.    In  1860  several  cargoes  of  an  ore  contain- 
