464 
FABRICATION  OF  SUGAR. 
possesses  only  that  slight  yellow  tint  which  belongs  to  the  purest 
syrups.  It  tastes  well,  is  deprived  of  the  saline  and  disagree- 
able taste  which  we  find  in  all  beet-syrups,  and  preserves  a  re- 
markable fluidity  and  limpidity.  The  crystallization  takes  place 
easily  and  the  crystals  are  white. 
As  a  final  proof  of  the  good  purification  of  the  saccharine 
juice  by  this  method,  if  we  add  to  a  boiled  syrup  a  proper 
quantity  of  water  to  bring  it  back  to  25°  or  30p  of  the  areome- 
ter, and  in  that  state  mix  it  with  a  large  excess  of  alcohol  at  90°, 
no  cloudiness  or  deposit  takes  place  even  after  several  days  ;  it 
no  longer  retains  a  trace  of  iron. 
Henceforth,  the  making  of  sugar  is  reduced  to  these  manipu- 
lations only  :  heating  the  saccharine  juice  in  a  boiler  with  some 
thousandth  parts  of  sulpha,te  of  lime  (natural  plaster  is  the 
best) ;  all  the  coagulable  matters  unite  in  a  firm  head  ;  the  clear 
juice  separated  from  this,  is  then  stirred  with  peroxide  of  iron. 
After  the  separation  of  the  oxide,  nothing  remains  to  be  done 
but  to  evaporate  the  water  ;  that  is  to  boil  down. 
The  hydrated  peroxide  of  iron  must  be  in  the  state  of  a  firm 
paste.  A  litre  (quart)  weighs  about  1145  grammes  (2j  lbs.) ; 
it  contains  from  70  to  80  per  cent,  of  water.  The  quantity  to 
be  employed  varies  with  the  juice  ;  it  is  never  more  than  8  or  10 
per  cent  of  the  juice,  which  amounts  to  2  per  cent,  about  of  the 
solid  matter,  the  rest  being  water.  After  its  action  on  the 
syrup  it  takes  a  black  color,  shrinks  and  separates  easily  from 
the  liquid.  After  it  has  been  used,  it  is  only  necessary  to  wash 
it  with  warm  water,  after  having  left  it  exposed  to  the  air,  in  order 
to  give  the  organic  matter  which  it  has  absorbed  time  to  be  de- 
stroyed, so  that  the  deoxidized  portion  may  take  again  the  oxy- 
gen which  it  has  lost.  It  may  be  used,  as  is  seen,  over  and  over 
again  indefinitely,  and  requires  but  little  expense  for  its  regener- 
ation. This  fortunate  property  renders  the  question  of  the 
quantity  to  be  employed  of  but  little  importance. 
I  will  add  in  conclusion,  that  even  now,  its  price  is  much  be- 
low that  of  animal  charcoal,  for  it  may  be  supplied  at  5  or  6  f. 
per  100  kilog.  ($8  to  $12  per  ton),  and  this  price  will  doubt- 
less be  much  reduced  hereafter. — Journ.  Frank.  Inst.,  March, 
1861,  from  Cosmos. 
