PREPARATION  OF  LIQUID  TARTRATE  OF  POTASH,  ETC.  257 
added  in  exces3,  will  be  regained.  The  alterations  in  this  pro- 
cess are  the  addition  of  potash,  the  employment  of  soda  in  slight 
excess,  the  boiling  of  not  longer  than  half  an  hour,  and  the  use 
of  much  less  water. 
From  crude  tartar  The  hard  crusts  of  crude  tartar  contain 
more  tartaric  acid  than  the  powder,  which  is  mixed  with  some 
earthy  matter.  The  crusts  contain  about  eleven  or  twelve  per 
cent,  tartrate  of  lime,  but  their  value  as  compared  with  cream 
of  tartar  is  100:80 ;  from  this  it  follows  that  the  same  quantity 
of  potash,  but  less  soda  is  to  be  taken.  The  tartar  must  be 
very  finely  powdered ;  the  deeply  colored  liquid  cannot  well  be 
filtered  ;  it  is  to  be  cooled  down  to  between  25  and  35°  C,  (75  to 
95°  F.)  when  the  white  of  an  egg,  previously  well-beaten,  is  mixed 
with  it,  and  the  liquor  heated  again  to  the  boiling  point.  The 
crystals  require  a  recrystallization,  the  last  portions  several 
times;  the  remaining  mother  liquor  is  best  precipitated  by  muriatic 
acid,  but  the  precipitate  is  colored,  and  the  color  enters  into  the 
Rochelle  salts  prepared  from  it.  The  author  could  not  remove 
the  coloring  matter  either  by  chlorine  or  by  alum;  after  boiling 
with  animal  charcoal  the  liquid  filters  well,  but  is  not  much  de- 
colorized. The  last  portions  of  all  the  above  mother  liquors 
may  be  rendered  turbid  from  traces  of  lime  ;  they  then  require 
to  be  boiled  over  and  filtered.  10  parts  of  Rochelle  salts  were 
obtained  from  7  parts  of  commercial  cream  of  tartar,  and  from 
8-8  parts  of  crude  tartar. 
The  author  found  that  100  grs.  Rochelle  salt,  perfectly  neu- 
tral, when  dissolved  in  150  grs.  of  water  took  up  2-5  grs.  of 
tartrate  of  lime,  part  of  which  separated  on  cooling,  but  after 
twelve  hours  the  liquor  still  contained  f  gr.  of  the  lime-salt  in 
solution  ;  the  same  quantity  of  distilled  water  did  not  dissolve 
any  appreciable  quantity  of  tartrate  of  lime. — Archiv  der 
Pharmacie,  1858,  Aug.,  149-156.  J.  M.  M. 
ON  THE  PREPARATION  OF  LIQUID  TARTRATE  OF  POTASH, 
AMMONIA,  AND  PEROXIDE  OF  IRON. 
By  M.  Carrie. 
The  potassio-tartrate  of  iron  being  incapable  of  preservation 
in  aqueous  solution,  on  account  of  its  tendency  to  rapid  decora- 
17 
