ANoV^XrPi9ir4m' }  Methods  for  Determination  of  Calomel  515 
Table  II. 
1\0. 
Gms.  HgCl 
bms.  JN  a2CU3 
Cc.  N/10 
AgNOs 
Cc.  N/10 
KCNS 
Gms.  HgCl 
found 
Per  cent  found 
in  mixtures 
I 
0.8000 
0.2000 
40.OO 
6.13 
O.7960 
2 
0.8000 
0.2000 
40.OO 
6.12 
O.7968 
7Q  6/1 
3 
0.6000 
O.4OOO 
30.OO 
4.61 
O.5981 
4 
O.60OO 
O.4OOO 
30.00 
4-56 
0-5993 
5 
0.6000 
O.4OOO 
30.00 
4.61 
0.5981 
59-85 
6 
O.40OO 
0.6000 
25.OO 
8.O4 
0.3996 
7 
O.400O 
0.6000 
25.OO 
8.06 
0.3991 
39-94 
8 
0.2000 
0.8000 
15.00 
8.48 
0.1999 
9 
0.2000 
0.8000 
15.OO 
8-43 
0.1985 
19.92 
It  must  be  admitted  that  the  results  obtained  for  this  table  are  a 
little  low,  due  either  to  a  passing  of  the  end  point  in  the  titration,  or 
to  the  reverse  reaction  6  which  occurs  when  the  silver  chloride  is  not 
removed  before  the  excess  of  silver  nitrate  is  titrated. 
The  third  table  shows  some  of  the  results  of  the  analyses  of 
several  samples^  of  calomel  tablets  by  the  sodium  peroxide  method 
and  the  checks  made  by  some  of  the  other  methods  of  analysis.  The 
table  is  condensed,  showing  only  the  average  of  duplicate  determina- 
tions in  each  case.  This  table  is  intended  to  give  an  idea  of  how  the 
amount  of  calomel  found  by  different  methods  varies  with  the  con- 
ditions imposed  by  each  method. 
Table  III. 
No. 
Grains  per 
tablet 
claimed 
Grains  by 
sulphide 
method 
Grains  by 
volume 
of  Hg 
Grains  by 
volume 
of  HgCl 
Grains  by 
iodide 
method 
Grains  by 
Na202 
method 
Per  cent,  of 
labelled 
value 
found  by 
Na20o 
method 
I 
1. 000 
O.992 
I.030 
IO3.O 
2 
1. 000 
0-775 
O.870 
87.O 
3 
0.250 
0.2I2 
O.19O 
O.252 
100.8 
4 
1. 000 
I.OIO 
O.982 
98.2 
5 
1. 000 
I.070 
I.030 
103.0 
6 
0.250 
O.3OO 
O.252 
100.8 
7 
0.500 
0.529  - 
0.525 
105.0 
8 
0.250 
0.333 
0.147 
98.8 
9 
0.250 
O.208 
O.260 
O.204 
81.6 
10 
0.250 
O.230 
O.239 
O.258 
103.2 
11 
0.500 
0-459 
0-494 
98.8 
12 
1. 000 
I.O95 
O.946 
94.6 
Average   97.9 
"Rosanoff  and  Hill,  /.  Am.  Chem.  Soc,  29,  269  (1907). 
