Atoj^ne,ri876arm'}  Gleanings  from  the  Foreign  Journals.  271 
When  powdered  white  precipitate  is  dropped  into  an  open  flask, 
filled  with  chlorine,  it  becomes  strongly  heated,  after  a  few  minutes, 
and  assumes  an  appearance  of  ebullition,  followed  either  by  an  explo- 
sion or,  more  frequently,  by  the  appearance  of  a  greenish  flame,  free 
nitrogen,  nitrogen  chloride  and  mercuric  chloride  being  formed. 
The  action  of  bromine,  upon  white  precipitate,  was  found  to  be 
very  analogous  to  the  foregoing. — Pharm.  Jour,  and  Trans.,  1876, 
March  11,  from  Ber.  D.  Cbem.  Ges.,  vol.  viii. 
Mr.  Charles  Rice,  having  observed  detonations  occurring  while 
triturating  white  precipitate  with  tincture  of  iodine,  reports,  in 
"  New  Remedies,"  for  February,  that  the  addition  of  carbolic  acid 
prevents  the  explosion  and  generates  some  iodoform,  equal  to  about 
two  per  cent,  of  the  iodine  employed.  Without  alcohol,  iodine  and 
white  precipitate  produce  no  iodide  of  nitrogen,  nor  does  a  solution 
of  iodine  in  carbolic  acid,  without  alcohol,  produce  iodoform.  The 
investigations  were  instituted  on  noticing  that,  while  making  an  oint- 
ment composed  of  Tinct.  iodinii  3ss.  Hydrarg.  ammon.  gr.ii,  and 
Ung.  acidi  carbol.  ^i,  a  sudden  fading  of  color  took  place,  and  the 
resulting  ointment  was  entirely  white. 
An  assay  of  persian  opium  was  recently  made  by  W.  D.  Howard  ;  it 
had  been  sent  to  England  as  "  perfectly  pure,"  and  yielded,  not  pre- 
viously dried :  morphia,  crystallized  from  alcohol,  10*40  ;  codeia 
(anhydrous),  0*29  ;  narcotina,  2*50  ;  thebaina,  0*57  ;  cryptopia,  0*09  per 
cent.,  and  a  trace  of  papaverina. — Pharm.  four,  and  Trans.,  1876, 
March  11. 
Impure  Potassium  Iodide. — Thos.  F.  Best  has  found,  in  five  samples, 
the  following  excess  of  alkali,  consisting  chiefly  of  carbonate:  5*44, 
5*35,  2*32,  1*78  and  0*53  per  cent.  Commercially  pure  iodide  should 
not  contain  more  than  from  0*15  to  0'20  per  cent. — Ibid. 
Detection  of  Free  Mineral  Acids  in  Vinegar. — Witz  has  proposed 
methylanilin-violet  for  this  purpose.  A.  Hilger,  in  experimenting 
with  it,  observed  that  pure  vinegar  does  not  affect  the  color,  but  on 
the  addition  of  sulphuric  acid  the  color  is  changed,  with  one-fifth  per 
cent,  to  blue,  with  one-half  per  cent,  to  blue-green,  and  with  one  per- 
cent, green.  Similar  changes  occur  with  muriatic  acid,  one-tenth  per 
cent,  producing  a  blue,  one-fifth  per  cent,  a  green  color,  and  with  one 
per  cent,  the  color  disappears.    Much  smaller  quantities  of  free  min- 
