3IO  Solubility,  etc.,  of  Acid  Carbonates,  etc.  {^"^-^.^^I'S^^"^- 
No.  5  contained  considerable  cinchonia;  Nos.  8,  9  and  10  yielded 
a  strongly  colored  solution,  containing  some  cinchonia,  and  in  Nos.  9 
and  10  cinchonidia  in  considerable  quantities.  The  quinine  was  evi- 
dently impure.  No.  4  dissolved  with  much  difficulty,  and  required  a 
large  amount  of  ether  to  take  up  the  precipitated  alkaloid.  The  pills 
were  probably  overheated  in  coating. 
With  these  exceptions,  the  quinine  employed  in  making  the  pills 
seem  to  have  been  of"  unexceptional  quality,  and  only  deficient  as  to 
quantity. 
A  recent  assay  of  the  pills  of  one  manufacturing  firm,  which  in  my 
first  experiments  I  found  to  contain  but  three-fourths  of  the  quantity 
of  quinine  claimed  by  the  label,  yielded  more  satisfactory  results,  the 
quantity  being  now  fully  up  to  the  standard.  These  pills  also  seem  to 
have  been  overheated  in  the  process  of  manufacture ;  they  dissolve 
pretty  readily,  but  the  quinine  will  scarcely  crystallize  from  a  neutral 
solution  in  water  containing  fifteen  grains  to  the  ounce. 
We  do  not  intend  to  let  this  subject  rest  here.  As  soon  as  the  facts 
can  be  brought  together,  we  propose  to  publish  the  results  of  assays  of 
sugar-coated  pills  from  all  the  prominent  manufacturers,  giving  their 
names,  which  have  hitherto  been  suppressed.  It  is  time  that  manufac- 
turing pharmacists  be  made  to  realize  that  honesty  for  them  is  the  best 
policy. — Detroit  Review  of  Phar.  and  Med.,  June,  1875. 
SOLUBILITY  AND  DISSOCIATION  OF  THE  ACID  CARBONATES 
OF  POTASSIUM,  SODIUM  AND  AMMONIUM. 
BY  H.  C.  DIBBITS. 
The  loss  of  carbonic  acid  when  solutions  of  these  salts  are  exposed 
to  the  air  has  long  been  noticed.  A  portion  of  the  salt  appears  to  be 
decomposed  in  the  solution,  and  as  the  carbonic  acid  passes  olF,  fresh 
quantities  of  the  salt  are  successively  decomposed,  until  the  whole  is 
transformed  finally  into  the  neutral  carbonate.  In  a  closed  vessel  the 
carbonic  acid  first  set  free  tends  by  its  presence  to  hinder  the  further 
evolution  of  the  gas,  and  the  decomposition  is  arrested  with  a  com- 
pleteness dependent  on  the  pressure.  On  the  other  hand,  if  the  layer 
of  gas  above  the  surface  of  the  liquid  be  constantly  removed,  either  by 
keeping  the  vessel  in  a  vacuum  or  by  passing  a  stream  of  air  through 
the  solution,  the  salt  will  be  more  rapidly  converted  into  neutral  carbon- 
ate.   Hence  crystals  of  the  acid  carbonates  of  potassium  and  sodium 
