60    CULTIVATION  AND  PREPARATION  OF  CASTOR  OIL  IN  ITALY. 
The  height  of  the  Ricinus  varies  from  five  to  ten  feet,  accord- 
ing to  the  soil,  so  that  the  husbandmen  have  to  take  into  con- 
sideration its  probable  growth,  in  order  to  allow  a  sufficient 
space  for  the  development  of  the  branches.  It  is  calculated  that 
the  Veronese  territory  alone  yields  an  annual  produce  of  over 
five  million  kilogrammes  of  seed,  being  less  than  the  quantity 
required  by  the  manufacturers,  who  are  thus  obliged  to  use  a 
portion  of  foreign  seed. 
The  preparation  of  the  oil  is  conducted  with  great  care,  so 
that  even  the  last  integument  is  removed  before  the  seed  is  sub- 
jected to  pressure.  For  this  purpose,  the  grains  are  passed 
through  a  machine  consisting  of  two  large  revolving  wooden 
rollers,  beneath  which  is  placed  a  powerful  winnowing  machine 
for  the  separation  of  the  seed  from  the  covering,  now  become 
broken  by  the  action  of  the  cylinders.  As  a  further  guarantee, 
a  number  of  little  girls  are  employed  as  sorters,  and  for  this 
purpose  are  usually  seated,  when,  placing  the  seed  before  them 
by  small  quantities,  they  reject  those  from  which  the  seed-coat 
has  been  imperfectly  removed,  as  well  as  the  damaged  and  rancid 
grains,  throwing  the  good  ones  into  baskets  placed  beneath. 
Every  manufactory  of  any  importance  has  at  least  five  or  six 
hydraulic  presses,  which  are  placed  in  a  room  heated  in  winter 
to  a  temperature  of  about  70°  Fahr.  Strong  coarse  hempen 
press-bags,  about  fourteen  inches  wide,  are  always  kept  ready, 
and  in  each  is  placed  about  three  kilogrammes  of  cleaned  seed. 
The  bag,  being  longer  than  wide,  folds  over  when  in  the  press, 
and  between  it  and  the  superposed  one  is  placed  a  sheet  of  iron 
that  has  been  heated  to  about  90°  Fahr.  The  presses  usually 
contain  from  twenty  to  thirty  bags,  which  have  a  thickness  of 
rather  less  than  two  inches  each.  All  the  oil  which  flows  from 
this  pressure  is  of  the  first  quality.  The  marc  is  now  ground  in 
a  mill,  and  again  placed  in  the  bags  ;  the  sheet  iron,  as  usual,  is 
placed  between  each  layer,  and  the  whole  gently  heated  up  to 
about  100  Fahr.,  when  it  is  again  subjected  to  pressure,  the 
result  of  which  is  a  further  yield  of  straw-colored  oil,  much  used 
in  the  manufacture  of  printer's  ink,  etc.,  etc.  The  blanched  seeds 
sometimes  yield  a  total  of  40  per  cent,  of  oil.  The  first  quality 
is  kept  in  a  warm  place,  (in  summer  just  beneath  the  roof,)  for 
some  days,  and  deposits  a  quantity  of  mucilaginous  and  fatty 
