466 
Seidlitz  Powders. 
( Am.  Jour.  Pharm. 
I     October.  1900. 
bonate,  and  the  rochelle  salt  per  cent,  correspondingly  lessened  to 
make  100. 
It  would  probably  convey  a  better  idea  of  the  value  of  the 
powders  if  they  were  to  be  compared  with  the  official  powders, 
judging  from  the  amount  of  anhydrous  rochelle  salt  found  in  the 
samples.  In  this  way  both  the  absolute  weight  of  the  powders 
and  their  composition  would  be  taken  into  consideration.  For  this 
purpose  the  mean  of  the  two  weights  given  was  taken  as  the 
average  weight  of  the  powders  of  each  druggist,  and  the  total 
quantity  of  anhydrous  rochelle  salt  in  the  sample  calculated  from 
the  results  of  the  analysis.  No.  I  being  again  taken  as  the  exam- 
ple, the  mean  of  the  two  weights  is  4-55  grammes.  Two  grammes 
of  the  mixture  required  12-2  c.c.  of  normal  sulphuric  acid  to 
neutralize  the  ash  from  the  rochelle  salt.  12*2  c.c.  are  equal  to 
1-279  grammes  of  anhydrous  rochelle  salt,  -104835  X  12*2  = 
1*278987.  If  2  grammes  of  the  mixture  contain  1*279  grammes  of 
rochelle  salt,  4-55  grammes  would  contain  2*909  grammes,  2: 
1*279  :  :  4-55  :  2-909,so  that  each  of  the  powders  of  that  particular 
druggist  contains  about  3  grammes  of  anhydrous  rochelle  salt. 
The  official  powder  contains  about  5*77  grammes  of  anhydrous 
rochelle  salt. 
blub  powders. 
No. 
Weights 
in 
Grammes. 
Results  of 
Qualitative 
Analysis. 
Sodium 
Bicarbonate. 
Rochelle 
Salt. 
Anhydrous  Rochelle 
Salt  in  Average 
Powder. 
1 
f  4*4 
I  47 
Traces  of  iron  and  "1 
chlorides.  J 
26  8  per  cent. 
73"  1  per  cent. 
3  grammes. 
2 
f  10-4 
Traces  of  iron  and  "I 
sulphates.  J 
23-89  •« 
76-1    "  " 
7-08  " 
t 
f  11-85 
\  n-6 
Traces  of  calcium  \ 
sulphates  and  iron.  J 
26-32  "  " 
73*65  " 
7"37  jjfjft 
4 
f  io'6 
I  10-4 
Traces  of-  chlorides  ) 
and  sulphates.  j 
23-48  "  " 
76-52  '« 
7-26 
5 
{■":  } 
Trace  of  sulphates. 
41-03  "    ,  " 
58-52  "  " 
4-98 
6 
f  84 
I  77 
Traces  of  iron  chlo-  ) 
rides  and  sulphates,  j 
268  " 
73-19  " 
5*21 
U.S. P. 
10*333 
25-0   "  " 
75-0  " 
577 
