596  Preparation  of  Syrups  by  Percolation.  {^"^'ilZ'^lt'"^- 
THE  PREPARATION  OF  SYRUPS  BY  PERCOLATION. 
By  Samuel  W.  Gadd,  Ph.G. 
From  an  Inaugural  Essay. 
•  The  author  is  in  favor  of  preparing  most  syrups  by  the  cold  process^ 
and  describes  the  operation  as  follows  : 
Take  a  funnel,  for  ordinary  operations  of  the  capacity  of  about  five 
pints,  the  angle  of  which  is  about  fifty-five  degrees,  and  having  a  wide 
throat.  Insert  a  small  piece  of  sponge  loosely  in  the  throat  of  the 
funnel,  to  prevent  the  particles  of  sugar  from  passing  through.  Add 
the  sugar,  pour  over  it  the  requisite  amount  or  a  portion  of  the  men- 
struum, insert  a  stopper  in  the  mouth  of  the  funnel  and  set  aside  for  a 
short  time  ;  then,  removing  the  stopper,  return  for  repercolation  the 
portion  of  liquid  which  immediately  flows  ;  that  following  will  be  a 
saturated  solution.  In  my  experiments  I  learned  that  a  tunnel  having 
the  specified  angle  is  much  better  than  a  cylindrical  percolator,  or  a 
funnel  having  a  greater  angle.  For  in  a  cylindrical  percolator,  the  col- 
umn of  sugar  being  so  tall,  the  portion  of  liquid  at  the  upper  part 
becomes  saturated,  and  will  occupy  too  much  time  in  passing  through. 
If,  on  the  other  hand,  a  funnel  having  a  greater  angle  be  used,  the 
liquid  in  its  downward  passage  will  continuously  cause  the  bulk  of 
sugar  to  depress  in  the  centre  until  it  reaches  the  stopping  in  the  throat 
of  the  funnel,  when  the  remaining  portion  of  liquid  will  pass  through 
unsaturated,  and  leave  a  portion  ot  sugar  on  the  sides  of  the  funnel. 
This  difficulty  does  not  occur  if  a  funnel  be  used  having  nearly  the 
specified  angle,  but  the  sugar  sinks  uniformly  as  the  liquid  passes  out^ 
the  menstruum  thus  taking  up  all  the  sugar,  and  passing  out  as  a  satu- 
rated syrup.  If  it  be  required  to  make  a  considerable  quantity  of  syrup, 
as  the  sugar  in  the  funnel  sinks  fresh  portions  of  sugar  and  menstruum 
may  be  added  alternately,  without  having  been  previously  weighed  or 
measured  ;  only  care  is  necessary  not  to  add  more  menstruum  than  the 
sugar  requires,  and  the  amount  will  be  readily  ascertained  by  one  who 
has  performed  the  process  but  once  or  twice.  The  result  will  be  pre- 
cisely the  same  as  if  the  sugar  were  weighed  and  the  menstruum  mea- 
sured out,  and  the  flow  will  be  continuous  as  long  as  the  additions  are 
ir.ade.  Simple  syrup  thus  obtained  near  the  temperature  of  6o°F. 
indicated  a  specific  gravity  of  1*324  at  69°F.  This  is  slightly  above 
that  of  the  officinal  syrup,  which  is  1*317.  However,  if  that  specific 
gravity  be  desired,  it  ,may  readily  be  obtained  by  adding  13*65  cubic 
