552 
CLARIFICATION  OF  SACCHARINE  LIQUIDS. 
as  shown  in  the  following  principal  results  in  the  manufacture  of 
beet-root  sugar : 
1.  To  completely  do  away  with  the  use  of  fresh  animal  char- 
coal. 
2.  To  abolish  revivification  at  a  high  temperature  (kilns  for  re- 
vivification, &c.) 
3.  To  greatly  reduce  the  quantity  of  charcoal  used  in  the 
course  of  the  work,  and  thus  to  effect  a  notable  economy. 
4.  To  obtain  sugars  of  a  superior  quality,  with  a  larger 
yield,  without  changing  the  apparatus  now  in  use. 
5.  To  reduce  considerably  the  net  cost  of  sugar. 
Now,  to  point  out  this  new  method.  In  the  ordinary  manu- 
facture, a  filter  filled  with  granulated  charcoal  lasts  from  twelve 
to  twenty  .four  hours.  The  absorbing  properties  of  the  charcoal 
then  appear  to  be  exhausted,  and  have  to  undergo  revivifying 
processes,  the  principal  being  calcination  in  a  closed  vessel  at  a 
high  temperature.  The  animal  charcoal  thus  revivified  does 
not  completely  recover  its  primitive  qualities,  and  its  value  as 
an  absorbent  is  reduced  one-half,  and  sometimes  more. 
In  the  ordinary  method,  all  the  absorbing  properties  of  the 
animal  charcoal  are  supposed  to  be  exhausted  at  the  same  time, 
and  the  object  of  the  revivifying  process  is  to  restore  them  equally 
and  simultaneously. 
The  following  is,  on  the  contrary,  the  fundamental  idea  of  our 
method  : — 
1.  Granulated  charcoal  plays  a  manifold  part,  and  has  various 
absorbing  powers,  which  act  independently,  and  do  not  become 
exhausted  simultaneously. 
2.  In  the  successive  revivification  of  the  absorbing  properties 
of  animal  charcoal,  according  as  they  become  exhausted,  by 
various  means  appropriate  to  the  nature  of  the  matters  the 
charcoal  has  absorbed. 
3.  In  the  possibility  of  augmenting  at  will  the  energy  of  the 
absorbing  properties  of  the  charcoal,  and  thus  to  render  its  re- 
fining action  on  juices  and  syrups  more  complete. 
4.  In  obviating  any  necessity  for  a  temperature  higher  than 
that  of  boiling  water  or  free  steam. 
By  investigating  the  process  of  the  filtration  of  juices  and 
syrups,  we  find  that  the  exhaustion  of  the  absorbing  properties 
