Am.  Jour.  Pharm. 
Sept.,  1886. 
Manufacture  of  Ceresin. 
431 
a  temperature  of  180°  C,  and  even  higher,  by  which  means  an  almost 
complete  decomposition  of  the  sulphuric  acid  and  carbonization  pf  the 
substances  separated  by  it  is  effected.  In  some  smaller  factories  where 
the  operations  are  conducted  at  a  much  lower  temperature,  the  acid, 
charged  with  the  impurities,  collects  at  the  bottom  of  the  vessel*  as  a 
black  tarry  mass  that  is  easily  separated. 
In  whatever  way  the  operation  is  conducted,  it  is  necessary  first  to 
free  the  crude  ozokerite,  as  delivered  from  the  melters  of  Borislaw  in 
Eastern  Galicia,  from  the  small  quantity  of  water  that  it  always  con- 
tains; for  which  purpose  it  is  dried  by  heating  it  to  130°  C,  at  which 
temperature  the  water  is  entirely  driven  off.  The  mineral  wax  re- 
quires to  be  heated  very  slowly  to  avoid  sudden  ebullition  of  the 
melted  mass,  through  the  superheating  of  the  water,  and  small  pieces, 
of  the  crude  wax  are  thrown  into  it  whenever  it  threatens  to  rise.  In 
some  cases  this  heating  is  effected  in  the  same  boilers  as  the  heating 
with  sulphuric  acid  ;  in  others  a  special  vessel  is  used  which  allows  of 
the  deposit  of  mechanically  mixed  impurities  at  the  bottom.  The 
vessels  for  the  preliminary  boiling,  which  should  be  of  a  capacity  suf- 
ficient for  a  day's  product,  are  heated  either  over  a  bare  fire  or  are 
jacketed  and  heated  by  steam.  In  the  former  case  the  apparatus 
takes  the  form  of  an  alembic,  consisting  of  a  hemispherical  boiler 
with  dome  and  cooling  worm,  in  which  any  vapor  of  the  light  oil 
given  off  during  the  melting  is  condensed.  When  the  heating  is  ef- 
fected by  steam,  the  small  quantities  of  hydrocarbon  carried  away 
with  the  steam  do  not  necessitate  any  arrangement  for  condensation. 
In  carrying  out  the  first-mentioned  method  of  bleaching,  where 
the  temperature  is  raised  to  180°  C,  the  mixture  of  the  ozokerite  with 
the  sulphuric  acid  is  effected  either  by  means  of  an  iron  or  copper 
stirrer  worked  by  hand  or  by  a  mechanical  agitator.  Although  the 
latter  arrangement  would  appear  in  principle  to  be  much  the  more 
rational  of  the  two,  it  is  not  the  most  used,  even  in  the  larger  manu- 
factories, in  consequence  of  practical  difficulties  that  have  not  yet 
been  satisfactorily  overcome.  After  the  earth-wax  has  been  freed 
from  water  it  is  placed  in  the  acidifying  vessel  with  a  mixture  of 
vitriol  and  fuming  sulphuric  acid  in  proportions  corresponding  to  the 
quality  required  ;  it  is  then  gradually  heated  with  constant  stirring  to 
180°  C,  at  which  temperature  the  sulphuric  acid  is  almost  completely 
driven  off.  After  neutralization  of  the  last  traces  of  acid  and  partial 
decolorization,  the  mixture  is  allowed  to  stand.     The  tolerably  clear 
