Am.  Jour.  Pharm.l 
August,  1883.  J 
Tinctura  Ferri  CJuoridi. 
389 
1000  cc.  distilled  water.  Theoretically,  1  cc.  of  this  solution  should 
be  equivalent  to  0*0056  gm.  pure  iron  ;  but  from  a  number  of  deter- 
minations made  with  pure  iron  wire,  it  was  ascertained  to  be  equal  to 
0  00537  gm.  iron,  and  this  number  was  employed  as  the  "factor  of 
correction. 
To  5  gm.  of  the  tincture  weighed  accurately,  3  gm.  of  metallic  zinc, 
with  dilute  HgSO^  was  added,  and  the  mixture,  heated,  excluded  from 
air  until  effervescence  ceased.  It  was  then  cooled  and  quickly  titrated 
with  potassic  permanganate  solution,  until  a  pink  coloration  of  the 
liquid  occurred.  The  number  of  cc.  used  was  52*  1  ;  multiplied  with 
0*00537,  it  indicated  0*279777  gm.  iron ;  but  from  this  number  was 
subtracted  0*023896,  the  known  amount  of  iron  contained  in  the  zinc 
as  impurity,  which  gives  0*25588  gm.  in  5  grams,  or  5*1176  per  cent, 
of  iron  present  in  the  tincture ;  this  is  equal  to  14*8357  per  cent,  of 
Fe^Clg,  and  to  24*6395  per  cent,  of  re2CJ6.12H20. 
The  following  tables  will  show  quite  a  variation  in  the  amount  of 
iron,  etc.,  present,  even  when  the  specific  gravities  are  the  same.  This 
can  be  easily  explained  by  the  variations  in  the  specific  gravities  of 
the  Liq.  ferri  chloridi  and  alcohol  used. 
Used  5  gm.  of  tincture. 
Percentage  in  tincture  of 
Spec.  gray. 
q 
Total  iron. 
Iron  in  zinc. 
Iron  in  tinc- 
ture. 
Iron. 
3 
6 
Q 
0/ 
cc. 
•965 
52^1 
•279777 
•023896 
•25588 
5-1176 
14-8357 
24-6395 
•970 
52-1 
•279777 
•023896 
•25588 
5^1176 
14  ^8357 
24-6395 
•965 
39^5 
•212115 
•023896 
•188219 
3-7642 
10-9124 
18  ^1137 
•970 
51-5 
•276555 
•023896 
•252659 
5-0532 
14-6435 
23-8367 
•965 
50^1 
•269037 
•023896 
•245141 
4  ^9028 
14-213 
23  ^6562 
1  -005 
57^4 
•308234 
•040828 
•25741 
5  ^1482 
14-9241 
24-6405 
•967 
52^0 
•279240 
•023896 
•25534 
5-1068 
14-8047 
24-6405 
•968 
48^1 
•268297 
•023896 
•2444 
4-888 
14-1704 
23  -5848 
•960 
48^6 
•262982 
•023896 
•239086 
4-7817 
13-8062 
23  ^0714 
•960 
53^3 
•286221 
•023896 
•262325 
5-2465 
15-0936 
25-3189 
