Ajanuary,Pi906!aJ'}      Inorganic  Chemistry  of  the  U.S.P.  29 
ized.  Not  more  than  3-75  c.c.  should  be  required.  This  amount 
deducted  from  the  30  c.c.  of  permanganate  V.  S.  added,  gives  the 
quantity  of  the  latter  which  was  decomposed  by  the  01  gramme  of 
sodium  nitrate  taken.  Each  cubic  centimeter  represents  0-0034285 
gramme  of  pure  sodium  nitrite. 
Example:       30  c.c.      —  375  c.c.    =  2625  c.c. 
26- 25  c.c  X  0-0034285  =   0-0899  -f  gramme.  , 
00899    X  IOO  =  89-9  per  cent. 
01 
The  Assay  ot  Sodii  Sulphis  is  changed  as  to  the  manipulation. 
In  the  old  Pharmacopoeia  a  weighed  quantity  of  the  salt  dissolved 
in  water  was  titrated  direct  with  decinormal  iodine  V.  S.,  using 
starch  as  the  indicator.  The  new  procedure  is  a  great  improvement 
upon  this.  In  it  the  sodium  sulphite  in  fine  powder  is  added  to 
50  c.c.  of  tenth  normal  iodine  V.  S.  contained  in  a  glass-stoppered 
bottle  of  about  IOO  c.c.  capacity.  After  standing  for  about  one  hour 
with  frequent  shaking,  the  mixture  is  titrated  with  tenth-normal 
sodium  thiosulphate  to  discharge  of  color. 
The  Assay  of  Sodii  Bisulphis  is  the  same  as  above. 
Strontium  Salts. — The  lactate  has  been  replaced  by  the  salicylate. 
The  bromide  and  iodide  are  still  official. 
The  starch  test  for  iodide,  in  strontium  bromide  is  replaced  by  the 
chloroform  head  test,  and  the  "  time-limit  test  for  heavy  metals  " 
takes  the  place  of  the  sulphide  test.  The  presence  of  barium  (be- 
cause of  its  poisonous  nature)  as  an  impurity  in  strontium  salts  is 
very  important  to  detect.  The  new  test  is  a  decided  improvement 
over  the  old  one.  The  tests  for  identity  are  the  same  as  before. 
The  assay  of  strontium  iodide  is  a  residual  titration  process  (that  of 
Volhard).  The  iodide  is  treated  with  measured  excess  of  tenth- 
normal silver  nitrate  V.  S.,  the  mixture  acidified  with  nitric  acid 
and  titrated  with  tenth-normal  potassium  sulphocyanate  V.  S.,  using 
ferric  ammonium  sulphate  as  indicator. 
Zinc  Salts. — No  remarkable  changes  are  observed,  except  that 
zinci  phenolsulphonas  and  zinci  stearas  have  been  added;  that  zinci 
phosphidum  has  been  dismissed  ;  and  that  zinci  valerianas  is  now 
called  zinci  valeras. 
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