6o4  Chemical  Notes.  {^i&ST* 
covered  when  lying  under  petroleum. — Bericbte  der  Chem.  GeselL,  xii, 
p.  1551. 
Effects  of  Alternate  Oxidation  and  Reduction. — E.  Drechsel  has  gotten 
some  very  interesting  results  by  rapialy  alternating  the  poles  of  a  gal- 
vanic battery  by  means  of  a  commutator  or  pole-changer  during  the 
electrolysis  of  solutions.  Thus  a  solution  of  ammonium  carbonate 
was  decomposed  using  platinum  electrodes.  The  evolution  of  gas  was 
rapid,  but  no  elevation  of  temperature  was  noticed.  After  about  eight 
hours  the  action  of  the  current  was  stopped  and  the  solution  concen- 
trated on  the  water-bath,  when  a  salt  crystallized  out  in  beautiful  white 
needles.  This  substance  contains  64-69  per  cent,  platinum,  and  is  the 
salt  of  a  platinum  base.  Its  solution  gives  with  concentrated  hydro- 
chloric acid  a  bright  green  precipitate,  and  with  nitric  acid  a  sky  blue 
crystalline  precipitate.  The  same  solution  submitted  to  electrolysis  in 
the  usual  way  became  strongly  heated,  but  no  platinum  was  dissolved. 
If  the  poles  be  changed  more  slowly  than  in  the  first  experiment,  the 
temperature  of  the  solution  rises.  If  this  be  overcome  by  artificial 
cooling,  there  is  obtained  at  the  end  of  the  experiment  a  salt  of  a  pla- 
tinum base  which  contains  less  platinum  (38*6  per  cent.),  and  with 
concentrated  hydrochloric  acid  gives  not  a  bright  green  crystalline  pow- 
der, but  nearly  colorless  microscopic  needles.  Prof.  Kolbe  proposes 
to  follow  up  this  study  on  the  decomposition  of  salts,  as  Prof.  Drechsel 
means  to  apply  the  method  to  different  experiments. — Jour,  fur  pr. 
Ck.,  20,  p.  378. 
Organic  Chemistry.—  On  the  Direct  Preparation  of  Propylene  Glycol 
from  Glycerin. — A.  Belchoubek  has  discovered  a  simple  method  of  con- 
verting glycerin  into  the  corresponding  diatomic  alcohol.  If  glycerin 
be  heated  with  sodium  in  the  form  of  sodium  amalgam,  a  transparent 
gummy  mass  is  produced,  from  which  the  separated  mercury  can  be 
poured.  This  mass  is  monosodium  glycerate,  according  to  Letts.  If 
this  be  submitted  to  dry  distillation  there  is  obtained,  among  other 
products,  a  liquid  which  when  purified  boils  at  1860  to  i88°C,  and 
shows  all  the  properties  of  the  propylene  glycol.  The  reaction  seems 
io  be  one  capable  of  general  application  for  reducing  an  alcohol  of  high 
atomic  value  to  one  of  lower  atomicity. — Ber.  der  Chem.  Gesell.,  xii, 
p.  1872. 
On  the  Phtalein  Hematoxylin. — The  publication  of  Meyer's  results  on 
the  dry  distillation  of  hematoxylin  (see  this  journal,  p.  491,  Oct.,  1879) 
