VARIETIES. 
461 
have  very  acid  reactions,  or  particularly  pungent  odors,  experience  must 
teach  ;  but  with  a  great  number  of  oils,  it  has  been  found  available,  even  with 
oil  of  bitter  almonds, — London  Ann.  of  Pharm.,  from  Archives  der  Pharm. 
The  presence  of  Hydro- Sulphocyanic  Acid  in  Commercial  Ammonia. — 
Mazade  has  found  hydro-sulphocyanate  of  ammonia  in  the  ammonia  ob- 
tained from  the  gas  works  at  Saint  Etienne.  The  red  color  which  arises 
from  the  combination  of  this  ammonia  with  acids  proceeds  from  the  action 
of  the  hydro-sulphocyanic  acid  on  the  iron  contained  in  the  acids  and  in 
the  ammonia.  Pelouze  has  recorded  that  Moreau  detected  hydro-sulpho- 
cyanate of  ammonia  amongst  the  products  of  the  distillation  of  coal,  and 
that  the  red  color  which  alum,  prepared  with  sulphate  of  ammonia  from 
gas  works,  exhibits,  results  from  this  salt. — London  Annals  of  Pharm.,  from 
Comptes  Rendus. 
A  Delicate  Test  for  Iodine.  By  Dr.  A.  Overbeck. — Comparative  experi- 
ments have  convinced  me  that  the  following  method  for  detecting  iodine  is 
the  most  delicate  of  any  yet  known  : 
Some  starch  or  sugar  is  poured  into  a  test  tube  with  concentrated  nitric 
acid,  and  heated  over  a  spirit  lamp  very  gently  until  a  violent  evolution  of 
gas  ensues.  The  spirit  lamp  is  then  removed,  and  the  gas,  which  now 
evolves  without  a  continuation  of  the  application  of  heat,  is  conducted  into 
the  fluid  to  be  tested,  to  which  a  solution  of  starch  has  been  added.  If  the 
fluid  contains  only  a  millionth  of  iodide  of  potassium,  a  blue  coloration  di- 
rectly results.  By  a  farther  introduction  of  the  gas,  the  iodide  of  starch 
precipitates  out  in  flocks,  and  deposits  itself,  when  at  rest,  as  a  compact 
massy  precipitate.  In  this  way  I  have  found  iodine  in  many  plants,  par- 
ticularly in  the  ashes  of  several  ranunculuses.—  London  Annals  of  Pharm., 
from  Archives  der  Pharmacie. 
Purification  of  Tallow  and  Grease. — Mr.  Wiggin,  of  Ipswich,  explained 
to  the  meeting  a  process  which  he  has  recently  patented;  for  melting  and 
purifying  tallow  and  other  kinds  of  grease.  The  process  consisted  in  heat- 
ing the  fatty  substance  in  the  state  in  which  it  is  removed  from  the  animal, 
with  a  small  quantity  of  sulphuric  acid  of  sp.gr.  1.3  to  1.45.  The  acid  dis- 
solves the  membrane  and  other  impurities  present,  acquiring  a  dark  color 
and  thick  syrupy  consistence,  while  the  fat  separates  in  a  state  of  great 
purity.  Some  samples,  which  were  shown  to  the  meeting,  of  tallow  and 
also  of  lard  which  had  been  prepared  by  this  process,  were  whiter  and 
more  free  from  flavor  than  those  prepared  in  the  usual  way. 
In  the  discussion  which  ensued,  it  was  suggested  that  the  fats  obtained 
by  this  process  were  probably  the  fatty  acids  resulting  from  the  decompo- 
sition of  the  neutral  fats  by  the  oil  of  vitriol ;  but  Mr.  Wiggin  stated,  that 
in  using  the  sulphuric  acid  at  the  density  indicated  no  decomposition  of  the 
fats  was  effected,  and  that  no  sulphurous  acid  was  evolved  in  the  process. — 
Pharm.  Joum.,  May  1,  1853. 
