442 
ON  SOME  CONSTITUENTS  OF  RHUBARB. 
which  never  fails  to  arrest  the  attention  of  a  stranger.  The  man 
who  is  hemmed  in  till  he  scarcely  feels  his  soul  his  own,  is  led  to 
treat  external  circumstances  in  a  somewhat  philosophic  manner. 
How  far  in  England  such  a  plan  would  answer,  it  is  not  for  me 
to  judge  ;  I  think,  however,  that  it  would  hardly  suit  our  national 
temperament. 
This,  at  least,  may  be  granted,  that  without  the  agency  of 
legal  interference,  there  is  no  more  diligent,  accurate,  or  scru- 
pulously conscientious  man,  than  the  English  Pharmaceutist ; 
nor  do  I  believe  that  in  any  other  profession,  trade,  or  calling, 
there  is  an  exhibition  of  a  more  continuous,  unwearying,  micros- 
copic application  than  in  an  English  Pharmacy. — London 
Pharm.  Jour.,  June,  1858. 
ON  SOME  CONSTITUENTS  OF  RHUBARB. 
By  Warren  de  la  Rue,  ph.d.,  f.  r.  s.  treas.  c.  s.,  and  Hugo  Muller,  ph.ix 
(Continued  from  page  368.) 
II. — Preparation  of  Chrysophane. 
The  investigations  of  the  deposit  of  the  "  Tinctura  Rhei  " 
affordi  d  us  an  opportunity  of  studying  the  properties  of  chryso- 
phane  in  connexion  with  the  other  constituents  of  the  rhubarb 
root,  and  enabled  us  to  devise  a  method  for  the  preparation  of 
chrys<  phane,  which  completely  removes  the  difficulties  hitherto 
experienced  in  the  extraction  of  that  substance  from  rhubarb. 
Having  observed  that  chrysophane  is  only  slightly  soluble  in 
alcohol,  but  that  it  dissolves  readily  in  glacial  acetic  acid,  amyl- 
alcohcl,  oil  of  turpentine,  coal  naphtha,  and  especially  in  benzol, 
and  in  the  lighter  oils  obtained  from  Burmese  naphtha,  to  the 
excluf  ion  of  the  greater  part  of  the  other  constituents,  it  became 
appai  ent  that  the  latter  solvents  might  be  used  with  great  advan- 
tage in  its  preparation.  A  few  preliminary  experiments  led  to 
the  selection  of  benzol,*  or  the  light  oils  of  Burmese  naphtha, 
*  Benzol  and  the  light  hydrocarbons  obtained  from  Burmese  naphtha 
appear  to  be  susceptible  of  a  very  general  application  in  experimental  re- 
search, as  they  are  of  great  value  in  separating  certain  classes  of  bodies 
from  others  of  a  different  nature.  As  examples  of  this  application,  we  may 
state  that  benzoic  acid  can  be  readily  separated  from  gum  benzoin  by  means 
