Am.  Jour.  Pharm. 
June,  1S8S. 
Laboratory  Notes. 
279 
Potassii  iodidum. — Geo.  A.  Curriden,  Ph.  G.,  prepared  some  potas- 
sium iodide  in  the  usual  manner,  by  treating  potassium  hydrate  with 
resublimed  iodine,  igniting  the  salt  with  charcoal,  and  crystallizing 
twice.  To  this  sample,  marked  No.  1,  the  pharmacopoeial  tests  for 
purity  were  applied,  and  four  commercial  samples,  procured  from 
manufacturers  in  New  York,  Philadelphia,  St.  Louis  and  Baltimore 
were  examined  in  the  same  manner,  giving  the  following  results  : 
Phaii:macopceiai, 
TESTS. 
No.  1. 
No.  2. 
No.  3. 
No.  4. 
No.  5. 
For    alkali  with 
litmus  paper. 
For  iodate. 
For    chloride  or 
bromide. 
For  sulphate. 
Weight  of  Agl. 
Faint  blue. 
Clear,  then 
yello^vish. 
Clear. 
Clear. 
1.415. 
Deep  blue. 
Brownish. 
Cloudy  at  once 
Cloudy  at  once 
1.368. 
Violet  blue. 
Purplish  blue 
immediately 
Cloudy  and 
precipitate. 
Clear. 
1.415. 
Violet  blue. 
Purplish  blue 
immediately. 
Cloudy  and 
precipitate. 
Clear. 
1.800. 
Deep  blue. 
Brownish. 
Cloudy  at 
once. 
Cloudy  at 
once. 
1.400. 
The  precipitated  silver  iodide  was  well  washed,  carefully  dried, 
brought  to  the  fusing  point  in  a  porcelain  crucible,  cooled  and  weighed. 
Of  the  commercial  samples,  Xo.  3  alone  yielded  the  theoretical  weight. 
The  weight  of  iodide  procured  by  the  remaining  three  commercial 
samples  being  less,  the  difference  was  probably  due  to  the  presence  of 
carbonate,  sulphate  and  iodate,  the  amount  of  which  impurities  was 
not  estimated. 
Hydrargyrum  ammoniatum. — This  compound  was  prepared  by  Wm. 
J.  Williams,  Ph.G.,  according  to  the  pharmacopoeial  process,  and  cor- 
responded with  all  the  requirements  of  the  pharmacopoeia.  This 
specimen  was  marked  No.  1.  Three  commercial  specimens  were  pur- 
chased, of  which  No.  2  alone  was  fusible.  The  pharmacopoeial  tests 
being  applied  to  all,  the  following  results  were  obtained : 
Pharmacopoeial 
tests. 
No.  1. 
No.  2. 
No.  3. 
No.  4. 
Heated  to  redness, 
Solubility  in  HCl, 
Lead  (solution  in 
acetic  acid  tested 
with  H2SO4), 
Completely 
volatile. 
Soluble;  no 
effervescence. 
Absent. 
2  per  cent, 
residue,  most- 
ly FeoOa. 
Soluble;  no 
effervescence. 
Absent. 
2}4  per  cent, 
residue,  most- 
ly Fe203. 
Soluble;  no 
effervescence. 
Absent. 
Completely 
volatile. " 
Soluble ; 
slight  effer- 
vescence. 
Absent. 
