13J:     SULPHUR  FOR  OIL  OF  VITRIOL  OR  SULPHURIC  ACID. 
mines.  The  pyrites  from  the  Tharsis  mines  are  now  used 
largely,  and  the  imports  of  Mr.  Mason's  ore  have  been  much 
reduced.  The  latter  usually  contains  about  50  per  cent,  of 
sulphur,  besides  3  or  4  per  cent,  of  copper.  The  Tharsis  mine- 
ral contains  48  to  50  per  cent,  of  sulphur,  and  4  to  5  per  cent, 
of  copper.  Both  kinds  are  much  the  same  in  their  working 
qualities ;  they  burn  well,  and  make  comparatively  little  dust  in 
breaking. 
Norwegian  Pyrites. — Many  mines  of  pyrites  occur  in  Norway, 
but  those  in  the  vicinity  of  Drontheim  are  the  most  important. 
The  Norwegian  ore  is  pretty  largely  imported  into  this  country, 
but  chiefly  to  the  Tyne.  The  largest  quantity  is  raised  in  the 
mines  Ytteroen,  the  annual  product  being  from  6,000  to  8,000 
tons.  It  consists  of  very  small  crystals,  is  of  good  quality, 
burns  well,  and  does  not  slag  in  the  kilns.  It  contains  about  44 
per  cent,  of  sulphur,  and  from  1  to  2  per  cent,  of  copper.  Un- 
der this  head  Mr.  Mactear  referred  to  a  second  quality  of  this 
mineral ;  to  an  excellent  variety  obtained  about  30  miles  from 
Drontheim,  and  containing  but  a  trace  of  copper ;  to  the  ores 
obtained  from  some  mines  opened  lately  near  Bergen  ;  and  to 
another  variety  which  comes  from  Nordland,  yielding  42  per 
cent,  of  sulphur. 
Swedish  Pyrites. — This  is  obtained  in  mining  for  copper  ores, 
and  is  said  to  exist  in  enormous  quantities,  but  at  present  the 
want  of  means  of  cheap  transport  to  convenient  shipping,  pre- 
vents it  coming  into  extensive  use.  A  few  cargoes,  however, 
have  found  their  way  to  Britain^  and  the  ore  itself  has  been 
found  to  work. 
Belgian  Pyrites. — Large  quantities  of  this  ore  are  imported, 
especially  to  the  Tyne — -the  freight  from  Antwerp  being  very 
low,  sometimes  only  6d.  per  ton.  The  mines  yielding  it  are  in 
the  districts  of  Liege  and  Namur,  and  are  worked  primarily  for 
lead  and  zinc  ores.  One  kind  is  called  alluvial  pyrites,  and  has 
the  form  of  coprolites,  and  few  of  the  pieces  weigh  more  than  a 
pound  each.  It  burns  well  if  used  along  with  Norwegian  or  other 
ores.    Another  resembles  a  slag  or  cinder,  and  often  contains 
