MANUFACTURE  OP  GLUCOSE.  19 
ble  in  concentrated  solutions  of  the  alkaline  phenates.  Water 
is  added  to  this  until  it  censes  to  cause  a  precipitate,  when  the 
liquid  is  exposed  in  wide  vessels,  to  facilitate  the  formation  of 
the  brown  bodies  and  their  deposit.  After  filtering,  the  ap- 
proximative quantity  of  organic  matter  held  in  solution  is  de- 
termined ;  formed  principally  of  phenic  acid  and  its  congeners, 
which  are  easily  displaced  by  jicids. 
The  phenic  acid  alwa}'s  is  the  last  to  separate,  so  that  it  is 
easy  to  disembarrass  it  of  its  associated  matter  and  brown  oxi- 
dized products  by  adding  caiefully  the  proportion  of  acid  deter- 
mined by  calculation,  so  as  to  precipitate  at  first  only  these 
matters,  and  by  means  of  several  trials  it  is  easy  to  arrive  at  the 
}  roper  point  to  stop,  so  as  to  retain  the  phenate  nearly  pure. 
The  acid  is  now  separated  and  rectified,  and  soon  crystallizes. 
As  a  little  water  prevents  its  crystallization,  the  author  removes 
it  by  passing  a  current  of  dry  air  over  the  phenic  acid  nearly 
boiling. 
The  crystallization  is  facilitated  by  cooling,  or  by  the  intro- 
duction into  it  of  a  small  quantity  of  the  crystallized  acid. 
The  author  insists  on  the  necessity  of  exposing  the  alkaline 
solution  of  the  acid  for  a  long  time  to  favor  the  resinification 
and  deposition  of  the  brown  matters ;  phenic  acid  is  always  im- 
pure when  it  is  colored. 
It  should  be  quite  pure  when  employed  to  make  picric  acid, 
because  the  impurities  waste  the  nitric  acid. 
Phenic  acid  often  contains  a  fetid  substance,  which  appears 
to  be  a  sulphuretted  compound  of  phenyl  or  cresyle.  It  is  re- 
moved by  rectification  from  oxide  of  lead. — From  Zeitsch.fur 
Chem.,  in  Journ.  de  jPharm.,  Nov.,  1865.  w.  p. 
MANUFACTURE  OF  GLUCOSE. 
By  M.  Maubre. 
In  this  process  the  saccharification  is  made  at  the  pressure  of 
six  atmospheres,  produced  by  steam  issuing  from  a  boiler  at 
820°  F.  The  boiler  is  ol  iron  plate,  lined  with  lead ;  it  contains 
a  leaden  tube  furnished  with  holes,  and  is  provided  with  waste- 
pipes,  valves,  etc. 
