AmAigurs'tPi89lm'}       Potassium  Iodide  and  Bromide.  381 
No.  6  was  alkaline,  contained  sodium,  freely  of  iodate  and  sul- 
phate, and  did  not  reach  the  purity  percentage  required. 
No.  7  was  all  right  in  every  respect,  except  that  it  did  not  con- 
form to  the  test  for  purity  percentage. 
No.  9  contained  traces  of  ammonia  only. 
No.  10  contained  traces  of  ammonia,  and  did  not  reach  the  purity 
standard. 
No.  1 1  showed  traces  of  ammonia,  and  did  not  reach  the  purity 
standard. 
No.  12  contained  traces  of  sulphate,  an  appreciable  amount  of 
ammonia,  and  did  not  come  up  to  the  purity  percentage  required. 
Samples  3  and  8  conformed  to  all  requirements  of  the  Pharma- 
copoeia. 
Next  best  was  No.  9. 
Sample  No.  6  was  the  worst  of  the  lot.  It  contained  a  considerable 
amount  of  iodate,  which  is  a  very  dangerous  contamination. 
POTASSIUM  BROMIDE. 
The  Pharmacopoeia  gives  a  large  number  of  tests  for  potassium 
bromide.    The  main  ones  are  as  follows  : 
The  salt  should  give  a  neutral  or  very  slightly  alkaline  reaction. 
The  addition  of  chloroform  and  chlorine  water  to  a  solution  of 
the  salt  should  not  develop  a  violet  tint. 
Potassium  carbonate  limit  is  given. 
The  salt  must  not  contain  sodium,  bromate,  iodine,  iron  and  alu- 
minium, arsenic,  lead  and  copper,  calcium,  barium,  sulphate,  iron. 
The  absence  of  more  than  3  per  cent,  of  chloride  is  determined 
volumetrically. 
Eight  samples  were  obtained  from  seven  firms.  Of  these,  two 
samples  were  from  one  firm. 
Sample  No.  2  contained  traces  of  sodium  and  sulphate. 
Sample  No,  3  showed  traces  of  sodium,  and  did  not  reach  the 
standard  for  absence  of  chloride. 
Sample  No.  4  was  all  right  in  every  particular,  except  that  it 
contained  too  much  chloride. 
Sample  No.  5  showed  traces  of  sodium  and  sulphate.  It  con- 
tained too  much  chloride. 
No.  6.  The  only  fault  found  in  this  sample  was  an  appreciable 
amount  of  sulphate. 
