GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
317 
By  titration  he  studied  its  oxidizing  power  on  a  proto-salt  of 
iron  directly,  and  in  the  presence  of  potassa,  and  found  the  used 
oxygen  in  both  cases  in  the  proportion  4:  3,  from  which  he  con- 
cludes the  existence  of  a  very  unstable  perchromic  acid=  Cr20^. 
If  the  chromate  of  chromic  oxide  Cr^Og,  CrOg  is  viewed  as  a 
binoxide  z=  CrO.^^  the  oxides  of  chromium  correspond  with  those 
of  manganium. — (Archiv  d.  Ph.  civ.  129-140.) 
Oxidation  of  Protosalts  of  Iron. — In  publishing  his  observa- 
tions on  the  preparation  of  acetate  of  iron,  Zippel  recommends 
to  expose  the  protochloride  of  iron  with  water  and  muriatic  acid 
.  for  several  weeks  to  the  air,  diluting,  heating  and  adding 
chlorate  of  potassa,  and  when  necessary,  muriatic  acid  ;  the 
solution  is  then  precipitated  by  ammonia  in  order  to  gain  the 
sesquioxide. — (Arch.  d.  Ph.  civ.  156-159.) 
The  yellow  color  of  a  decoction  of  Marsh  Mallow  Root  is  due, 
according  to  Gust.  Selle,  to  a  decomposition  of  its  constituents 
when  not  kept  perfectly  dry,  and  to  the  consequent  presence  of 
ammonia,  probably  from  asparagin. — (Arch.  d.  Ph.  civ.  160.) 
Oleum  Morrhum  ferratum. — 15  parts  protosulphate  of  iron 
are  precipated  by  14  p.  carbonate  of  soda,  the  precipitate  ex- 
pressed, and  after  the  addition  of  little  water  digested  for  2J 
hours  in  a  water  bath,  with  250  parts  cod  liver  oil.  The  deep 
brown  mixture  readily  becomes  clear  in  a  bottle,  and  soon 
thickens  on  exposure  to  the  air.  The  oil  is  said  to  contain 
about  1  per  cent,  of  iron  (Arch.  d.  Ph.  civ.  270,  271.) 
Umplastrum  Plumhi  W.  Lienau  rubs  the  litharge  with  oil 
to  a  thin  paste,  which  is  heated  to  80^0  (176^F).  When  the 
remainder  of  the  oil  has  been  heated  to  90^C  (194^F),  the 
litharge  is  added.  After  stirring  continually  for  J  or  J  hour, 
little  hot  water  is  added,  and  the  supply  kept  up  as  it  evaporates. 
With  a  well  regulated  heat,  the  plaster  is  finished  in  8  or  10 
hours,  and  a  good  glycerine  is  obtained. — (Arch.  d.  Ph.  civ.  274.) 
Pure  Carbonate  of  Soda  is  prepared  by  W.  Lienau  from  crude 
soda  by  dissolving  it  in  distilled  water,  diluting  with  6  or  8 
times  the  quantity,  and  precipitating  lead  and  iron  by  a  current 
of  sulphuretted  hydrogen.    The  sulphide  of  sodium  is  decern- 
