40 
SOLUBILITY  OF  CREAM  OF  TARTAR  IN  ACIDS,  ETC. 
48  hours  to  the  common  temperature  of  about  20°  C.  The 
residue  was  now  collected,  washed  with  very  little  water,  and 
the  dissolved  portion  ascertained  from  the  loss.  The  results 
were  as  follows  : — 
Mixture. 
Dissolved  Cream  of  Tartar. 
Proportion. 
1. 
8  oz.  water. 
28-50 
grains. 
1 
:  135 
2. 
a 
"  and  330 
grs 
T 
36-75 
u 
1 
•  104 
3. 
a 
"   "  80 
tt 
HC1 
274- 
a 
1 
14 
4. 
a 
"   "  163 
it 
KC1 
4-75 
it 
1 
808 
5. 
a 
"  "  119 
it 
N05 
307-50 
it 
1: 
12 
6. 
u 
a  n  222 
a 
KO  N05 
6-75 
1 
568 
7. 
a 
"  "  88 
u 
so3 
225 
1 
17 
8. 
u 
"  «  191 
(L 
KO  S03 
7-25 
u 
1: 
530 
9. 
it 
"   "  132 
a 
Ac 
30-75 
u 
1: 
124 
10. 
u 
u  u  216 
a 
KO,  Ac 
55-50 
it 
1: 
69 
If  cream  of  tartar  was  as  readily  decomposed  by  hydro- 
chloric acid  as  tartrate  of  lime,  there  ought  to  have  been  dis- 
solved in  experiment  No.  3  at  least  412  grains  ;  but  here,  as  well 
as  in  Nos.  5  and  7,  the  decomposition  is  incomplete.  Tartaric 
and  acetic  acids  increase  the  solubility  but  little,  while  chloride 
of  potassium  and  nitrate  and  sulphate  of  potassa  decrease  it 
considerably.  Acetate  of  potassa  is  decomposed  by  the  bitar. 
trate  on  digestion  ;  the  liberated  acetic  acid  appears  to  be  partly 
recombined  on  cooling. 
There  are  three  points  to  be  observed  in  the  purification  of 
cream  of  tartar  from  lime  by  muriatic  acid:  1.  Action  of  the 
dilute  muriatic  acid  upon  all  particles  of  the  cream  of  tartar. 
2.  Complete  removal  of  the  acid  liquid  ;  and  3.  Employment  of 
sufficient  muriatic  acid. 
Duflos'  original  direction  to  treat  the  crystals  of  cream  of 
tartar  with  the  dilute  acid,  will  perhaps  never  accomplish  the 
entire  separation  of  the  lime  ;  the  finer  it  has  been  powdered, 
the  better  will  its  purification  be  effected  ;  but  it  was  impossible 
to  obtain  the  preparation  free  from  lime  ;  by  following  the  direc- 
tions of  the  Prussian  Pharmacopoeia,  it  will,  however,  be  suffi- 
ciently pure  for  all  pharmaceutical  purposes. 
The  acid  is  best  removed,  by  stirring  the  mixture  repeatedly 
in  water  and  decanting ;  the  proportion  of  lime  remaining  be- 
