SULPHUR  FOR  OIL  OF  VITRIOL  OR  SULPHURIC  ACID.  435 
lead  or  antimony.  Belgian  ores  contain  from  40  to  50  per  cent, 
of  sulphur,  and  traces  of  thallium. 
Westplialian  Pyrites. — This  resembles  a  very  poor  fire-clay, 
or  shale,  in  appearance,  but  it  burns  well.  It  is  said  to  contain 
a  considerable  quantity  of  thallium.  The  analysis  gives  42  to  45 
per  cent,  of  sulphur- 
Italian  Pyrites. — Very  little  of  this  is  imported,  for  although 
it  contains  about  45  per  cent,  of  sulphur,  it  also  contains  9  or 
10  per  cent,  of  silica,  and  its  physical  properties  are  not  in  its 
favor. 
Irish  Pyrites. — This  is  obtained  from  the  Wicklow  mines, 
where  it  occurs  in  beds  of  great  thickness.  It  contains  from 
30  to  35  per  cent,  of  sulphur.  A  deposit  occurs  in  the  Vale  of 
Avoca  which  contains  about  44  per  cent,  of  sulphur. 
Cornish  Pyrites. — Under  this  head  the  author  included  the 
ore  from  the  mining  districts  of  Dorset,  Devon  and  Cornwall. 
It  is  got  in  the  dressing  of  the  lead  and  copper  ores,  and  usually 
contains  from  25  to  30  per  cent,  of  sulphur  and  1  or  2  per  cent, 
of  copper,  and  frequently  arsenic.  The  author  also  referred  to 
the  fact  that  Mr.  Vivian  is  making  sulphuric  acid  by  burning 
copper  pyrites  in  kilns  of  peculiar  construction. 
Coal  Brasses. — This  material,  also  called  "Scotch  gold,"  is 
largely  used,  and  is  a  cheap  source  of  sulphur  for  acid  to  be  used 
in  making  manures,  &c.  Even  when  well  cleaned  it  always 
contains  organic  matter,  and  possesses  other  disadvantages  ;  still 
it  is  useful  in  keeping  up  heat  in  the  kilns  if  used  along  with 
other  varieties. 
Cleveland  Pyrites. — Although  interesting  to  the  geologist, 
this  mineral  is  of  little  interest  to  chemical  manufacturers,  and 
the  author  said  he  only  knew  of  one  establishment  where  it  is 
used — one  near  Middlesbro'-on-Tees. 
The  author  concluded  his  paper  by  referring  to  the  sulphur- 
recovery  process,  patented  by  M.  Mond,  and  now  being  practi- 
cally applied  under  his  (the  author's)  care  at  St.  Rollox  Chemi- 
cal Works. — London  them.  News,  May,  8,  1868,  from  Proc. 
Philos.  Soc.  Glasgow. 
