398        EXAMINATION  OF  THE  SULPHATE  OF  QUINIA. 
of  crystallization  until  the  temperature  had  fallen  below  205°  ; 
and  the  temperature  fell  to  200°  before  general  rapid  crystalli- 
zation was  fairly  established  in  the  solution.  This  crystallization 
seemed  complete  in  four  or  five  hours,  but  the  flask  was  exposed 
at  ordinary  temperatures  for  nineteen  hours,  and  then  for  seven 
hours  was  kept  at  temperatures  between  55°  and  65°  by  means 
of  iced  water.  The  mother  water  was  then  quickly  separated 
and  set  aside  for  examination ;  and  the  crystals  washed  in  a  filter, 
drained,  dried  and  effloresced  at  212°,  and  weighed.  The  wash- 
ings were  then  evaporated  to  dryness  and  the  residue  weighed. 
These,  with  the  calculated  quantity  of  2Qn,  S03,  -f  8HO,  in  the 
mother  liquor,  (1  part  to  every  740  parts,)  =  -9223  gram.,  when 
added  together  and  corrected  for  the  loss  by  efflorescing,  give  a 
total  net  yield  of  25.3069  gram,  of  2Qn,  S03,  -f  8HO,  for  this 
ounce  of  commercial  salt,  indicative  of  a  loss  of  11.123  per 
cent.  The  loss  by  efflorescing  is  calculated  upon  Exper.  No.  1., 
and  the  residue  of  the  washings  is  assumed  to  be  all  disulphate 
of  quinia  and  water.  The  first  crop  of  crystals  of  this  experi- 
ment are  assumed  to  be  the  pure  officinal  salt,  and  are  to  be  used 
in  the  following  experiments  as  pure  effloresced  sulphate. 
^Experiment  No.  3. 
Similar  quantities  of  the  pure  and  impure  effloresced  sulphates 
were  placed  side  by  side  in  a  box  of  bibulous  paper,  and  allowed 
to  stand  exposed  to  the  ordinary  atmosphere  for  sixteen  hours. 
They  were  then  heated  for  two  hours  at  temperatures  from  200° 
to  218°,  and  again  exposed  at  ordinary  temperatures  for 
twenty  hours,  at  the  end  of  which  time  they  were  assumed 
to  have  attained  a  corresponding  condition  of  hydration, 
as  far  as  the  disulphate  of  quinia  was  concerned.  From  each 
of  these  salts  10  pgrams.  was  weighed  into  separate  capsules,  and 
the  capsules  and  contents  were  subjected  to  the  same  steam  heat, 
at  the  same  time,  for  eight  hours — five  hours  at  temperatures 
varying  between  220°  and  236° — and  three  hours  at  a  steadily- 
maintained  temperature  of  242°,  without  any  appearance  of 
fusing  in  either.  They  were  then  placed  under  a  bell  glass, 
over  sulphuric  acid,  for  fourteen  hours,  and  weighed.  The  pure 
salt  had  lost  -4577  gram.,  or  4-577  per  cent. ;  whilst  the  impure 
