1 30  lodo-Sulfhate  of  Chinioidin.         { Am£rur^7earm' 
Notwithstanding  the  different  circumstances  in  which  the  reagent 
was  applied,  the  results  seem  to  me  satisfactory. 
The  two  following  experiments  were  made  with  pure  quinia,  dried 
at  ioo°  C,  at  which  temperature  it  still  retains  water,  under  identical 
circumstances  : 
1*0664  gram  of  hydrated  quinia  gave  1*7266  gram  of  herapathite= 
164*5  Per  cent. 
1*055  gram  of  the  same  hydrated  quinia  gave  1*7343  gram  of  hera- 
pathite=i64*3  per  cent. 
Although  I  feel  convinced  that  this  process  of  estimating  the  amount 
of  quinia  in  a  mixture  of  Cinchona  alkaloids,  is  not  one  which,  even  in 
the  hands  of  inexperienced  persons,  shall  give  accurate  results  in  a  short  time, 
I  have  some  hope  that  in  the  hands  of  experienced  analysts,  it  may 
prove  a  satisfactory  one,  if,  before  applying  it,  they  study,  as  I  have 
done,  the  action  of  the  reagent  upon  solution  of  1  gram  of  quinia, 
quinidia,  cinchonia  and  of  cinchonidia,  each  of  them  separately  in  20 
grams  of  the  above-mentioned  acidulated  alcohol.  If  they  do  so,  they 
will  find  that  the  iodo-sulphates  of  quinia  and  of  quinidia,  thus 
obtained,  have  an  analogous  composition,  and  are  identical  with  the 
compounds  described  by  Herapath,1  whilst  the  iodo-sulphates  of  cin- 
chonia and  cinchonidia  have  a  different  composition  from  the  former, 
and  both  require  more  iodine  to  be  transformed  into  the  optical  iodo- 
sulphates  described  by  Herapath.  In  the  meantime,  they  will  find  that 
of  all  these  iodo-sulphates,  that  of  quinia  is  the  most  insoluble  in  alcohol, 
as  has  been  stated  already  by  Herapath  in  the  paper  above  quoted,  and 
is  therefore  precipitated  the  first  of  all  and  alone  by  a  judicious  addition 
of  the  iodo  sulphate  of  chinioidin. 
I  do  not  in  the  least  pretend  to  have  exhausted  the  subject,  but  on 
the  contrary,  I  hope  that  my  paper  may  lead  to  a  still  better  process. 
Thus,  for  instance,  I  feel  some  hope  that  it  may  be  possible  to  apply 
the  alcoholic  solution  of  iodo-sulphate  of  chinioidin  to  volumetric 
analysis,  and,  therefore,  I  presented  a  specimen  of  it  to  Mr.  Sutton, 
the  author  of  the  valuable  work  "  On  Volumetric  Analysis,"  when  he 
was  so  kind  as  to  call  upon  me  at  the  Hague  last  summer. —  The  Phar. 
Jour,  and  Trans.,  December  11,  1875. 
1  "  Proceedings  of"  the  Royal  Society,"  vol.  ix,  p.  10. 
