Compound  of  Starch  with  Iodine.  27 
peculiarly  colored,  blueish-green-purple  coating.  The  lower  stratum 
is  of  a  bright  red  color.  Antimony  terchloride  is  therefore  a  very 
good  reagent  for  the  petroleum  oils. 
With  oil  of  turpentine  I  obtained  a  very  violent  reaction,  attended 
by  the  evolution  of  great  heat  and  the  deposition  of  a  yellowish  res- 
inous mass. 
Laboratory,  No.  18  Exchange  Place,  New  York. — American 
Chemist,  Nov.,  1873. 
NOTE  ON  THE  COMPOUND  OP  STARCH  WITH  IODINE. 
By  E.  Sonstadt. 
Some  starch  was  kept  for  more  than  two  months  in  a  solution  of 
salts  containing  more  free  iodine  than  the  starch  could  take  up.  The 
iodized  starch  was  then  washed  for  a  fortnight  on  a  filter,  by 
which  time  the  water  came  through  very  nearly  colorless ;  it  was  then 
further  washed  by  decantation  untrl  the  water  was  colorless  after 
settling.  The  iodized  starch  thus  prepared  was  black,  and  had  little, 
if  any,  odor.  A  portion  of  it,  air-dried,  was  found  to  contain  3*2  per 
cent  of  iodine.  Another  portion  was  then  heated  in  an  oven  for  a 
long  while  at  a  temperature  somewhat  higher  than  that  of  a  water- 
bath.  While  drying,  it  smelt  perceptibly  of  iodine,  but,  when  thor" 
oughly  dry,  it  was  perfectly  free  from  odor,  and  the  color  remained 
black.  This  stove-dried  compound,  heated  in  a  closed  tube,  gave  off 
no  trace  of  free  iodine,  but  a  small  quantity  of  a  yellowish  vapor  came 
off,  of  a  pungent  odor,  attacking  the  eyes,  and  condensing  in  the  cool 
part  of  the  tube  in  drops.  The  heat  was  then  raised  to  redness,  and 
the  charcoal  formed  examined  for  iodine,  which  it  proved  to  contain. 
The  stove- dried  compound  is  extremely  stable,  and  the  ordinary 
reagents  attack  it  very  slowly  ;  it  could  not  be  analyzed  by  treatment 
with  solution  of  thiosulphate  of  sodium,  or  of  chlorine.  A  solution  of 
the  former,  in  excess,  failed  to  decolorize  it  after  a  week's  treatment, 
with  frequent  shaking.  It  was  prepared  for  analysis  by  moistening 
it  with  a  strong  solution  of  hydrate  of  sodium,  and  heating  to  redness, 
and  the  iodine  was  estimated  in  the  solution  of  the  residue  by  chlo- 
rine-water. It  contained  3*2  per  cent  of  iodine,  the  same  percentage 
of  iodine  as  was  contained  in  the  air-dried  specimen. 
Another  portion  of  the  stove-dried  compound  was  charred  at  a 
gentle  heat,  continued  for  about  an  hour,  in  a  covered  crucible,  and 
