338 
ON  THE  USE  OF  BENZOLE. 
it,  was,  I  believe,  first  pointed  out  by  Mansfield.  He  took  the 
ordinary  naphtha,  distilled  it  in  a  still  with  a  double  head,  so  con- 
structed that  only  that  portion  of  the  naphtha  which  distils  at  the 
lowest  temperature  was  collected;  the  product  thus  obtained 
was  digested  with  oil  of  vitriol,  which  turned  it  black.  I  have 
found  it  necessary  that  this  part  of  the  process  should  be  repeat- 
ed at  least  twice,  or  the  proper  degree  of  purification  would 
not  be  effected.  The  benzole  thus  separated  was  now  washed 
with  water,  dried  with  anhydrous  sulphate  of  soda,  and  re-dis- 
tilled ;  it  was  then  exposed  to  a  freezing  temperature,  and,  when 
solid,  subjected  to  pressure,  when  the  pure  benzole  was  obtained  ; 
but,  for  the  purposes  I  have  to  point  out,  I  do  not  consider  this 
last  operation  necessary. 
Benzole,  thus  obtained,  is  a  clear,  volatile  liquid,  having  still 
a  distinct  odor  of  coal  gas,  but  more  aromatic  ;  it  is  quite  insolu- 
ble in  water,  and  is  excessively  inflammable ;  this  last  property 
renders  great  caution  necessary  in  conducting  the  processes  I 
am  about  to  describe.  Benzole,  in  its  powers  of  solution,  may 
be  likened  to  ether,  but,  from  its  low  price,  and  from  its  not  be- 
ing so  volatile  as  that  body,  it  possesses  practical  advantages  in 
working,  which,  I  think,  will  more  than  counterbalance  its  dis- 
agreeable odor  and  great  inflammability. 
The  first  application  of  benzole  I  have  to  describe  is  in  the 
preparation  of  quinine  and  its  allied  bases.  An  acid  infusion 
of  the  bark  was  prepared  in  the  usual  manner  ;  sufficient  caustic 
potassa  was  added  to  render  it  strongly  alkaline ;  it  was  then 
shaken  with  about  one-fourth  of  its  bulk  of  benzole ;  the  whole 
of  the  quinine,  quinidine,  quinoidine,  &c,  was  at  once  yielded 
to  that  agent.  I  found,  however,  that  the  cinchonine  was  not 
extracted  without  greater  difficulty.  The  benzole  was  distilled 
off,  leaving  the  mixed  alkaloids  as  a  slightly  yellow,  resinous 
mass,  which,  when  dissolved  in  weak  sulphuric  acid,  and  filtered, 
yielded  a  solution  from  which  the  white  bases  were  at  once  pre- 
cipitated, and  separated  in  the  usual  manner. 
This  process,  I  think,  would  not  answer  for  manufacturing 
quinine  on  a  large  scale,  but  I  find  it  is  a  very  elegant,  certain, 
and  easy  mode  of  performing  the  analysis  of  cinchona  barks, 
for,  if  moderate  care  is  used,  the  alkaline  liquid  remaining  after 
