GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
45 
salts  is  precipitated  by  an  excess  of  ammonia,  the  precipitate 
allowed  to  settle,  the  blue  copper  solution  is  first  filtered,  and 
the  oxide  of  iron  then  collected  upon  the  same  filter.  This  is 
washed  with  hot  water  until  the  filtrate  ceases  to  produce 
a  precipitate  with  ferrocyanuret  of  potassium,  and  then  washed 
back  into  a  porcelain  dish,  there  to  be  dissolved  by  pure  muriatic 
acid,  and  again  precipitated  by  an  excess  of  ammonia  ;  the  pre- 
cipitate is  treated  in  the  same  manner  as  before,  then  dried  in 
an  air-bath  and  incinerated  in  a  platinum  crucible  ;  the  previously 
ascertained  amount  of  ashes  of  the  filter  is  subtracted  from  the 
weight  of  the  whole  residue,  when  the  remainder  shows  the 
weight  of  sesquioxide  of  iron.  The  amount  of  copper  is  ascer- 
tained by  evaporating  from  the  filtrate  by  means  of  a  water 
bath  the  excess  of  ammonia,  acidulating  with  muriatic  acid,  pre- 
cipitating the  copper  with  sulphuretted  hydrogen,  washing  and 
oxidizing  with  nitric  acid  so  as  to  obtain  it  as  oxide  of  copper. 
Tartrate  of  Baryta. — Dr.  A.  Vogel,  jun.  and  Dr.  C.  Rei- 
schauer  have  published  in  Buchner's  Repertorium,1859,  337-348, 
researches  on  tartrate  of  baryta,  the  results  of  which  are  as  fol- 
lows : — This  salt  exists  in  an  amorphous  and  in  a  crystalline 
state  ;  when  freshly  precipitated,  it  is  flocculent  and  amorphous, 
but  soon  changes  into  the  crystalline  modification  which  rapidly 
subsides  in  heavy  granular  crystals.  A  characteristic  differ- 
ence between  these  two  modifications  is  their  solubility  in  water, 
the  amorphous  tartrate  dissolving  in  83,  the  crystalline  in  1300 
parts  of  water.  The  flocculent  precipitate  in  solution  of  baryta 
by  tartaric  acid,  or  in  chloride  of  barium  by  tartrate  of  potassa, 
may  be  dissolved  in  the  requisite  quantity  of  water,  from  which 
solution,  on  standing,  the  crystalline  tartrate  of  baryta  is  sepa- 
rated. 
Preparation  of  Bromide  and  Iodide  of  Potassium. — Professor 
Dr.  A.  Buchner  has  proposed  the  following  formula  for  the 
second  edition  of  the  new  Bavarian  Pharmacopoeia: — 2  oz.  iron 
filings  and  18  oz.  of  distilled  water  are  mixed  in  a  flask  with  3  oz. 
of  bromine  gradually  added,  and  agitated  until  the  liquid  has  as- 
sumed a  greenish  color,  when  it  is  filtered,  and  the  filter  washed 
with  distilled  water.  This  liquid  is  added  to  a  solution  of  1  oz. 
