12 
Laboratory  Notes. 
/Am.  Jour.  Pharm. 
(.       Jan.,  1886. 
Mercurous  Iodide. — According  to  George  A.  Haifa,  Ph.G.  this  com- 
pound is  best  made  by  precipitation  of  mercurous  nitrate  with  potas- 
sium iodide  and  may  then  be  obtained  of  a  yellow  or  green  color 
according  to  the  density  of  the  solution.  The  solution  of  mercurous 
nitrate  is  prepared  by  acting  upon  15,000  grs.  of  mercury  with  a 
cold  mixture  of  nitric  acid  6,000  grs.,  and  water  4,000  grs.,  placing 
the  vessel  in  cold  water  and  stirring  the  contents  constantly  until  the 
reaction  has  entirely  ceased;  the  white  crytalline  mass,  without  being 
separated  from  the  excess  of  metallic  mercury,  is  then  dissolved  in 
water  acidulated  with  nitric  acid  (1  oz.  to  the  gallon)  until  the  solution 
measures  four  pints. 
For  preparing  green  mercurous  iodide  mix  solution  of  mercurous 
nitrate  6  oz.  with  water  6  pints,  and  add  to  it  in  a  continuous  stream 
and  with  constant  stirring,  a  solution  of  potassium  iodide  3  oz.  in 
water  54  oz.,  decant,  wash  the  precipitate  with  water  and  dry  with- 
out the  aid  of  heat. 
For  preparing  yellow  mercurous  iodide  operate  in  the  same  manner, 
but  use  solution  of  mercurous  nitrate  2  oz.  diluted  with  water  8  pints, 
and  a  solution  of  potassium  iodide  1  oz.  in  water  4  pints.  This  salt 
darkens  much  more  quickly  when  exposed  to  the  light  than  that  made 
by  the  pharmacopoeial  process. 
Chloride  of  Gold  and  Sodium. — Two  commercial  samples  of  this 
salt,  examined  by  Alfred  Conarcl  Wood,  Ph.G.,  were  found  to  agree 
in  all  respects  with  the  pharmacopoeial  requirements,  except  the  per- 
centage of  metallic  gold,  which  was  ascertained  as  directed  by  the 
Pharmacopoeia,  by  treating  a  solution  of  0.5  gm.  of  the  salt  with  a 
clear  acidulated  solution  of  2  gm.  of  ferrous  sulphate. 
No.  1  yielded  0125  gm.  gold  =  25  per  cent. ;  deficiency  7'4  per  cent. 
No.  2     "       0-110  "     "    =22-      "  10-4 
Acetic  Ether. — Luther  P.  Bowers,  Ph.G.  has  examined  three  com- 
mercial specimens  of  acetic  ether  with  the  following  results :  One  was 
very  impure,  had  the  specific  gravity  *924,  was  extremely  acid  to 
litmus  paper,  effervesced  strongly  with  calcium  carbonate,  and  afforded 
clear  solutions  with  alcohol  and  ether,  but  would  not  dissolve  in 
chloroform.  10  c.c.  of  it  agitated  with  an  equal  volume  of  water, 
separated  an  ethereal  layer  of  7  c.c.  The  ether  had  an  empyreumatic 
odor  and  on  evaporation  left  a  yellowish  residue.  The  second  sample 
had  the  specific  gravity  '904,  effervesced  with  calcium  carbonate,  and 
showed  an  undue  loss  on  being  agitated  with  water,  but  was  much 
