MANUFACTURE  OF  CHLORINE,  ETC.  543 
able  manager  of  them, — has  actually  generated  chlorine  from 
which  bleaching-powder  has  been  made,  something  like  fifty  suc- 
cessive times. 
Hitherto,  the  principal  item  in  the  cost  of  chlorine  has  been 
that  for  native  peroxide  of  manganese.  Last  year,  in  Great 
Britain,  France,  Belgium,  and  Germany  together,  there  were 
produced  about  120,000  tons  of  bleaching-powder,  which  cost, 
on  an  average,  for  native  oxide  of  manganese,  not  much,  if  any 
less  than  £5  per  ton.  My  process  substitutes  of  this  cost  for 
native  oxide  of  manganese  a  cost  for  the  regeneration  of  manga- 
nite  of  calcium  not  exceeding  fifteen  shillings  per  ton  of  bleach- 
ing-powder, being  about  ten  shillings  for  lime,  one  shilling  for 
steam,  one  shilling  for  wages,  and  two  shillings  for  interest  and 
wear  and  tear.  Moreover,  whereas  hitherto,  at  least  in  this 
country,  and  in  all  but  an  extremely  few  exceptional  cases,  the 
•  production  of  a  ton  of  bleaching  powder  has  required  the  acid 
from  about  75  cwts.  of  salt :  my  compound  yields  chlorine 
enough  for  a  ton  of  bleaching-powder  from  the  acid  from  less 
than  45  cwts.  of  salt.  This  larger  yield  of  chlorine  is  mainly 
due  to  the  artificial  manganite' being  so  easily  soluble  that  it  can 
very  readily  be  caused  to  neutralize  from  95  to  99  per  cent,  of 
the  acid  employed,  which  is  a  very  much  larger  proportion  than 
can  be  neutralised  when  working  with  manganese  ores.  A  third 
very  important  advantage  of  the  new  process  over  the  old  one 
consists  in  this — that,  whereas  the  immense  quantities  of  acid 
which  escapes  neutralization  in  the  old  process  are  usually — and 
have  almost  necessarily  to  be — sent  into  the  rivers  as  free  acid, 
the  only  product  of  the  new  process  which  has  to  be  thrown 
away  is  a  perfectly  neutral  solution  of  chloride  of  calcium. 
Seeing  that  manganite  of  calcium,  or  CaMnOg,  is  only  of  the 
very  same  value  precisely  in  respect  of  the  quantity  of  chlorine 
which  it  can  liberate  from  a  given  quantity  of  acid  as  sesquioxide 
(otherwise  manganite  of  manganese,  or  MnMn03),  he 
well  to  explain  why  it  is  preferable  to  produce  and  re-produce 
the  former  rather  than  the  latter.  The  reasons  for  this  are  two. 
There  is,  firstly,  the  obvious  reason  that,  when  all  the  man- 
ganese is  converted  into  MnOg,  twice  as  much  work  is  done  per 
given  bulk  of  material  operated  upon  as  when  only  half  the 
