EXAMINATION  OF  THE  SULPHATE  OF  QUINIA.  403 
command ;  but  I  hoped  to  have  brought  the  subject  into  a  light 
sufficiently  interesting  and  important  to  induce  some  one,  better 
qualified,  to  take  up  and  pursue  the  subject. 
Experiment  No,  8. 
The  reserved  mother  liquor  of  Experiment  No.  2  weighed 
682.5475  gram.,  and  contained,  according  to  the  following 
equation,  based  upon  the  solubility  of  the  disulphate  of  quinia, 
.9223  gram,  of  that  salt.  For  as  740  :  1  : :  682.5475  gram.  : 
.92236  gram.  This  mother  liquor  was  evaporated  to  one-eighth 
its  bulk,  or  till  crystals  began  to  form  on  the  surface  of  the  hot 
liquor,  and  was  then  set  aside  to  crystallize.  These  crystals, 
when  washed,  dried,  effloresced  at  212°  and  cooled,  weighed 
1.6356  gram.  As  these  crystals  must  have  contained  nearly 
all  the  disulphate  of  quinia  that  remained  in  the  mother  liquor, 
it  is  requisite  to  subtract  the  .9223  gram,  less  8.8  per  cent., 
equal  to  .8412  gram,  of  effloresced  disulphate  from  their  weight. 
This  leaves  the  brown  crystalline  impurity  at  .7944  gram.  The 
remaining  mother  liquor  and  washings  were  then  evaporated 
together  to  dryness,  and  heated  for  some  hours  at  218°.  The 
red  brown  amorphous  residue  then  weighed  .7528  gram.  Thus 
the  total  impurity  of  a  saline  and  amorphous  character  contained 
in  one  ounce  of  the  commercial  salt  is  represented  by  the  fol- 
lowing formula : 
.7944+.7528  =1.5472  gram.,  or  6.074  per  cent. 
Experiment  No,  9. 
From  the  effloresced  crystalline  impurity  of  the  mother  liquor, 
from  Experiment  No.  8,  two  portions  of  .7  gram,  each  were 
weighed  off  at  the  same  time,  and  marked  E  and  F. 
Portion  E  was  dissolved  in  water  acidulated  with  sulphuric 
acid,  precipitated  by  solution  of  soda,  and  the  precipitate  washed, 
dried  and  fused,  when  it  weighed  .4837  gram. 
Portion  F  was  dissolved  in  water  acidulated  with  hydrochloric 
acid,  precipitated  with  solution  of  chloride  of  barium ;  and  the 
precipitate  when  washed,  dried  and  ignited,  yielded  .0662  gram. 
ofS03. 
The  combined  weight  of  this  acid  and  base  subtracted  from 
the  weight  of  the  effloresced  salt  used,  leaves  .1501  gram.,  or 
