PHARMACEUTICAL  NOTES  OF  TRAVEL. 
Ill 
days  the  chlorinated  lime  is  taken  out  of  one,  the  other  being 
filled  with  fresh,  and  so  on  alternately,  each  charge  being 
thus  subjected  to  the  gas  for  two  days.  The  workmen  exposed 
to  the  action  of  this  corrosive  gas  in  the  operation  of  charging  , 
and  emptying  the  chambers,  appear  to  become  so  habituated  to 
its  effects  as  to  live,  judging  from  one  specimen  we  saw,  to  a 
great  age.  The  delicate  tissues  of  the  lungs  and  the  lining 
membrane  of  the  air  passages,  resist  for  years  a  corrosive  action 
which  completely  destroys  the  teeth. 
The  oxide  of  manganese,  after  serving  its  purpose  of  decom- 
posing the  muriatic  acid,  exists  in  the  state  of  chloride  ;  this  is 
restored  again  to  the  condition  of  oxide  for  future  use,  by  the 
following  process  : — it  is  first  treated  with  lime,  by  which  the 
iron  is  separated,  and  then  with  carbonate  of  lime  which  pre- 
cipitates carbonate  of  manganese ;  this,  by  calcination,  is  con- 
verted into  oxide  for  use  again  in  the  decomposition  of  muriatic 
acid.  This  process  is  a  patent  belonging  to  the  concern,  and 
the  invention  of  one  of  the  partners. 
The  manufacture  of  sulphuric  acid  is  carried  on  by  a  process, 
which  is  also,  I  believe,  original  with  a  member  of  this  firm. 
The  sulphur  is  burned  in  small  furnaces,  communicating  with  a 
large  horizontal  pipe  ;  into  this  is  poured  near  one  extremity,  a 
peculiar  acid  mixture  or  compound  called  nitro-sulphuric  acid, 
consisting  of  concentrated  sulphuric  acid  saturated  with  nitric 
acid. 
When  mixed  with  water  this  liquid  has  the  property  of  giving 
off  nitrous  acid  in  profusion,  and  being  discharged  with  water 
into  the  tube  containing  gaseous  sulphurous  acid,  converts  it  into 
sulphuric  acid  ;  this  runs  off  into  iron  vats  lined  with  lead  which 
are  heated  till  it  is  concentrated  to  a  certain  specific  gravity  ;  these 
vats  show  a  deposite  of  sulphate  of  lead,  which,  to  a  great 
extent,  protects  them  from  the  action  of  the  acid.  The  acid  is 
now  run  into  a  platinum  still,  which  is  placed  over  a  very  hot 
fire,  and  the  concentrated  acid,  as  it  runs  off,  is  cooled  by  pass- 
ing through  horizontal  troughs  of  water,  and  into  leaden  cold 
water  baths.  The  method  of  throwing  the  acid  into  receiving 
vessels  in  convenient  positions  for  filling  carboys  without  the 
aid  of  a  pump,  is  by  the  pressure  of  air  forced  into  the  tubes. 
From  the  sulphate  of  soda  left  after  the  liberation  of  muria- 
