Am.  Jour.  Pharm, 
Nov.,  1SS9. 
Gleanings  from  the  German  Journals. 
565 
determinations  22*38,  23  and  23*70  per  cent. — H.  Hager,  Pharm. 
Centralhalle,  1889,  565. 
Oxygen  may  be  obtained  perfectly  pnre,  and  without  the  aid  of  heat, 
by  dissolving  58  grams  ferricyanide  of  potassium  in  as  little  water  as 
possible  and  mixing  with  100  cc.  of  a  3  per  cent,  hydrogen  perox- 
ide solution;  through  a  funnel-tube  solution  of  potassium  hydrate  is 
added,  when  a  steady  evolution  of  oxygen  occurs,  ceasing  so  soon  as  a 
neutral  solution  is  obtained,  but  capable  of  being  revived  by  the  addi- 
tion of  more  KOH  as  long  as  ferricyanide  and  hydrogen  peroxide  are 
present  in  the  generator.  From  the  above  quantities  two  liters  of  pure 
oxygen  are  obtainable ;  being  generated  in  alkaline  solution,  chlorine 
and  carbon  dioxide  cannot  contaminate  it.  The  solution  in  the  gener- 
tor  contains   only   ferrocyanide   of    potassium;   the   reaction  is: 
C6Fe2  (CN)12  f  2KOH  +  H202  =  2K4Fe  (CN)6  +  2H20  +  02.  Dr. 
Georg  Kassner,  Chem.  Ztg.,  1889,  1302  and  1338. 
Another  method  for  obtaining  a  steady,  current  of  oxygen  is  to  place 
in  a  Kipp's  generator  chlorinated  lime  which  has  been  compressed 
into  cubical  or  other  form,  and  an  acidified  (HC1  or  HNOg)  solution 
of  hydrogen  peroxide.  CaOCl2— H202=CaCl2+H20-f02.  The  acid  is 
necessary  to  dissolve  the  impurities  in  the  chlorinated  lime.  From 
one  liter  2 '88  per  cent.  H202,  300  gm.  bleaching  powder,  and  57  cc. 
HC1  of  sp.  gr.  1*17  were  obtained  18"5  liters  of  oxygen,  almost  the 
theoretical  yield ;  the  oxygen  may  contain  carbon  dioxide  and  small 
quantities  of  chlorine,  which  may  be  removed  by  passing  the  gas 
through  a  wash  bottle  filled  with  potassium  hydrate  solution.^- J.  Vol- 
hard  (Liebig's  Ann),  Pharm.  Ztg.,  1889,  617. 
Color  Reactions  of  Phenols. — The  various  colors  obtained  with  phe- 
nols by  use  of  a  mixture  of  sulphuric  and  nitric  acids,  Paul  Gutzkow 
attributes  to  the  formation,  first,  of  nitrous  acid  from  the  nitric  acid 
and  the  behavior  of  nitrous  acid  towards  the  phenols.  From  a  careful 
series  of  experiments  he  finds  that,  starting  with  nitrous  acid,  mere 
traces  are  sufficient  for  the  production  of  characteristic  colors.  The 
method  giving  best  results  was  to  place  in  a  watch  crystal  set  upon  a 
white  background  10-15  drops  of  strong  sulphuric  acid,  adding  a 
small  fragment  of  the  solid  phenol,  or  one  drop  of  the  solution,  and, 
after  waiting  a  few  moments  to  allow  the  acid  to  cool,  from  a  partly 
filled  bottle  of  amyl  nitrite,  allowing  the  vapor  to  flow  over  the  sulphu- 
ric acid  for  fifteen  seconds;  by  gentle  agitation  the  colors  are  developed 
in  a  short  time. 
