24 
Development  of  the  Sugar  Industry,  j 
Am.  Jour.  Pharm. 
January,  1915. 
a  second  and  a  third  mill,  and  in  some  cases  to  fourth,  fifth,  and 
sixth  sets  of  rollers ;  in  the  latter  case  there  would  be  18  rollers  in 
the  milling  plant  in  addition  to  the  two  rollers  of  the  crusher.  Be- 
tween the  mills  a  thin  stream  of  water  is  sprayed  on  the  cane,  which, 
being  eliminated  by  the  succeeding  rollers,  carries  with  it  more  and 
more  of  the  residual  sucrose.  This  process  is  called  maceration 
and  requires  to  be  carefully  controlled. 
The  pressure  on  the  mills  is  gradually  increased,  as  the  cane 
advances,  by  powerful  hydraulic  presses ;  when  the  fibre  leaves  the 
Fig.  8.— Roller  mill. 
final  rollers  it  still  contains  between  40  and  50  per  cent,  of  moisture 
(usually  nearer  50  per  cent.)  with  a  small  residue  of  unextracted 
sugar.  The  best  mills  extract  over  95  per  cent,  of  the  total  sugar 
in  the  cane. 
The  expressed  juice  from  the  crusher  and  mills  is  then  pumped 
into  tanks,  called  defecators,  where  it  is  treated  with  milk  of  lime 
to  neutralize  its  acidity;  after  this  it  is  heated  to  boiling  by  steam 
coils.  The  lime  combines  with  the  organic  acids  of  the  juice  to 
form  insoluble  compounds,  and  the  heat  coagulates  the  albuminous 
