272  PREPARATION  OP  STARCH  FROM  CASSAVA. 
Secondly — The  grating  is  also  in  favor  of  cassava,  as  compa^ec^ 
to  arrowroot,  in  almost  an  equal  rate.  But, 
Thirdly — I  would  not  grate  at  all  ;  but  quote  from  pages  of 
a  known  scientific  work,  and  I  suppose  the  site  of  operations  to 
be  the  old  works  of  a  thrown  up  sugar  estate,  and  unfortunately 
many  such  a  spot  can  too  readily  be  found.  The  manufacture 
is  arrowroot,  but  of  course  the  same  works  would  equally  do  for 
cassava,  and  I  may  just  observe  that  the  manufacture  is  in  the 
Island  of  St.  Vincent,  and  I  have  no  doubt  its  completeness  is 
the  cause  of  the  superior  price  obtained  for  the  St.  Vincent  ar- 
rowroot, which  is  just  threefold  the  price  of  Jamaica  arrowroot, 
in  the  English  market  ; 
"  The  skinned  roots  are  thrown  into  a  large  cistern,  with  a 
perforated  bottom,  and  then  exposed  to  the  action  of  a  copious 
cascade  of  water.  The  cleansed  roots  are  next  put  into  the 
hopper  of  the  mill,  and  are  subjected  to  the  powerful  pressure  of 
two  pairs  of  polished  rollers  of  hard  brass,  the  lower  pair  of 
rollers  being  set  much  closer  than  the  upper.  The  starchy  mat- 
ter is  thus  ground  into  a  pulp  which  falls  into  the  receiver  placed 
beneath,  and  is  thence  transferred  to  large  and  fixed  copper 
cylinders,  tinned  inside,  and  perforated  at  the  bottom  with 
numerous  minute  orifices,  like  a  kitchen  drainer.  Within  these 
cylinders,  wooden  paddles  are  made  to  revolve  with  great  velocity, 
by  the  power  of  a  waterwheel,  at  the  same  time  that  a  stream  of 
pure  water  is  admitted  from  above.  The  paddle  arms  beat  out 
the  fecula  from  the  fibres  and  parenchyma  of  the  pulp,  and  dis- 
charge it  in  the  form  of  a  milk  through  the  perforated  bottom  of 
the  cylinder.  This  starchy  matter  runs  along  pipes,  and  then 
through  strainers  into  large  reservoirs,  where  after  fecula  has 
subsided,  the  supernatant  water  is  drawn  off.  The  drying-house 
on  the  Hopewell  estate  is  constructed  like  the  hot-house  of  an 
English  garden,  but  instead  of  plants  it  contains  four  dozen  of 
drying-pans  made  of  copper,  seven  and  a  half  feet  by  four  and 
a-half,  and  tinned  inside.  Each  pan  is  supported  on  a  car- 
riage, and  they  run  on  rails;  immediately  after  sunrise  theae 
carriages,  with  their  pans  covered  with  white  gauze  to  exclude 
dust  and  insects,  are  run  out  into  the  open  air,  but  if  rain  be  ap- 
prehended they  are  run  back  under  the  glazed  roof.  In  about 
four  days  the  fecula  is  thoroughly  dry  and  ready  to  be  packed.'* 
