HILLEBUAND. 
COLORIMETRIO PJSTIMATION OF CHROMIUM. 
39 
Table I. 
[Ten cubic centimeters standard represent 1 milligram chromic oxide.] 
Test solution. 
Comparison stand 
> T o. 
Content.-, 
as 
chromic 
oxide. 
Chromic 
oxide 
found. 
Chromic 
oxide 
present. 
E 
nor. 
Chromic 
oxide 
found. 
Stand- 
ard. 
Diluted 
with 
water. 
Cubic 
centime- 
ters. 
HO 
added. 
c. c. 
c. c. 
c. c. 
Mgs. 
Mgs. 
Mgs. 
Mgs. 
Per cent. 
1 alO 
a 90 
5 
44.00 
0.5 
0.98 
1 
— 0. 02 
98. 
2 &20 
bSO 
5 
21.00 
.5 
1.92 
2 
— 
.08 
96.0 
3 10 
60 
10 
14.60 
1.0 
4.06 
4 
+ 
.06 
101. 5 
4 
40 
60 
9.7 
14.25 
.97 
4. 05 
4 
+ 
.05 
101.2 
10 
13. 95 
1.0 
4.17 
4 
+ 
.17 
101. 1 
10 
14.30 
1.0 
4.11 
4 
+ 
.11 
102.9 
10 
14.20 
1.0 
4.13 
1 
+ 
.13 
103.3 
5 
40 
60 
10 
14.65 
1.0 
4.05 
•1 
+ 
.05 
101.4 
10 
15.65 
1.0 
3.90 
4 
— 
.10 
97.5 
6 
40 
60 
10 
15.25 
1.0 
3.96 
4 
— 
.04 
99.0 
10 
14.30 
1.0 
4.11 
4 
+ 
.11 
102.9 
10 
13.15 
1.0 
4.32 
4 
+ 
.32 
108.0 
10 
14.75 
1.0 
4.04 
4 
+ 
.04 
101.0 
20 
29.50 
2.0 
4.04 
4 
+ 
.04 
101. 
7 50 
50 
10 
9.75 
1.0 
5.06 
5 
+ 
.06 
101.2 
8 | 50 
50 
10 
10.00 
1.0 
5.00 
5 
.00 
100.0 
9 60 
40 
10 
7.20 
1.0 
5.81 
6 
— 
.19 
96.7 
10 75 
25 
20 
6.65 
2.0 
7. 505 
7.5 
+ 
.005 
100.1 
20 
6.60 
2.0 
7.519 
7.5 
+ 
.019 
100. 2 
10 
3.15 
1.0 
7.605 
7.5 
+ 
. 105 
101. 4 
15 
4.70 
1.5 
7.610 
7.5 
+ 
.11 
101.5 
11 10 
10 
10 
10.15 
1.0 
0.992 
1 
— 
.008 
99.2 
20 
19.75 
2.0 
1.006 
1 
— 
.006 
100. 6 
12 10 
11 
10 
10. 60 
1.0 
1.02 
1 
+ 
.02 
102.0 
13 14. 2 
26.9 
10 
18.60 
1.0 
1.43 
1.42 
+ 
.01 
100.7 
20 
35.70 
2.0 
1.47 
1.42 
+ 
.05 
103.5 
14 15 
24.35 
10 
16. 55 
1.0 
1.48 
1.5 
— 
.02 
98.7 
15! 16 
20 
10 
13.30 
1.0 
1.54 
1.6 
— 
.06 
96.2 
20 
24.30 
2.0 
1.63 
1.6 
+ 
.03 
101.9 
16 31.9 
20.6 
10. 5 
8.10 
1.05 
2.96 
3.19 
— 
.23 
92.8 
20.5 
14.20 
2. 05 
3.10 
3.19 
— 
.09 
97.2 
17 
62. 05 
22.3 
20 
7.00 
2.0 
6.25 
6.205 
+ 
. i:. 
100.7 
40 
12.00 
4.0 
6.49 
6.205 
+ 
.285 
104.6 
Mean percentage found, 100.5. 
a Color in this dilution too faint. 
b Limit of dilution for clear distinction of color in a thickness of 3.3 cm. 
