ON  THE  USE  OP  BENZOLE. 
837 
lime  well  washed,  to  remove  all  the  potash  salt ;  the  first  washings 
being  mixed  with  the  stronger  solution,  and  the  latter  reserved 
to  be  used  for  the  first  washing  waters  of  another  operation.  The 
tartrate  of  lime  thus  produced  may  be  employed  in  the  manu- 
facture of  tartaric  acid.  The  solutions  of  bicarbonate  of  potash 
are  next  evaporated  to  dryness  in  an  iron  pan,  by  which  means 
the  bicarbonate  is  changed  into  sub-carbonate,  which  may  be 
calcined  in  a  reverberatory  furnace,  when  a  carbonate  of  potash 
will  be  produced,  sufficiently  pure  for  most  manufacturing  pur- 
poses. If  required  of  greater  purity,  it  may  be  purified  in  the 
usual  manner.  The  carbonic  acid  gas  may  be  produced  in  any 
known  manner.  The  same  process  is  applicable  to  the  manu- 
facture of  soda,  substituting  neutral  tartrate  of  soda  for  the  neu- 
tral tartrate  of  potash  above-mentioned  London  Pharmaceutical 
Journal,  Jan.  1854. 
ON  THE  USE  OF  BENZOLE  IN  THE  PREPARATION  OF 
VEGETABLE  ALKALOIDS.* 
By  John  Williams. 
The  application  of  Benzole  to  the  elimination  of  various  vege- 
table alkaloids  having  engaged  my  attention  for  some  time 
past,  I  venture  to  lay  the  present  paper  before  you,  more  in  the. 
hope  of  its  receiving  practical  adaptation  from  your  hands,  than 
from  any  idea  that  the  subject  has  been  worked  out  to  its  fullest 
extent. 
First,  then,  a  few  words  respecting  benzole  : 
This  important  and  interesting  body  was  first  discovered  Jby 
Faraday,  and  named  by  him  bicarburetted  hydrogen  ;  it  was  af- 
terwards produced  by  decomposition  of  benzoic  acid  by  heat  in 
presence  of  lime  or  baryta,  and  hence  named  benzole ;  it  has, 
however,  since  been  proved  to  exist  in  very  considerable  quan- 
tities in  coal-tar  naphtha,  or  that  portion  of  the  liquid  products 
of  the  destructive  distillation  of  coal,  which  floats  on  water, 
boils  below  the  temperature  of  212°  F.,  and  congeals  to  a  solid 
mass  at  32°.  The  ordinary  coal-tar  naphtha  of  commerce  is  a 
very  impure  product ;  the  mode  of  separating  the  benzole  from 
*  Read  before  the  "  Chemical  Discussion  Society,"  Oct.  27th,  1853. 
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