In these the iodide was added direct to the solution containing the copper, which was afterwards diluted to 100 c.c. and titrated. In another series the iodide was added after the dilution to 100 c.c., and the results were:—
| Potassic iodide added | 1.5 gram | 3 grams | 5 grams | 10 grams |
| "Hypo" required | 20.0 c.c. | 20.1 c.c. | 20.0 c.c. | 20.0 c.c. |
Effect of Varying Bulk.—In these experiments, 20 c.c. of copper sulphate were taken, 3 grams of potassic iodide added, and also water to the required bulk.
| Bulk | 20.0 | c.c. | 100.0 | c.c. | 200.0 | c.c. | 500.0 | c.c. |
| "Hypo" required | 20.0 | " | 20.0 | " | 20.0 | " | 19.9 | " |
In the last of these experiments the colour was discharged at 18 c.c., but gradually returned until 19.9 c.c. had been run in. It will be seen that considerable variation in bulk does not interfere.
Effect of Acetic Acid.—These experiments were like the last series mentioned, but the bulk was 100 c.c., and varying amounts of acetic acid were added.
| Acetic acid added | 0 | c.c. | 1.0 | c.c. | 5.0 | c.c. | 10.0 | c.c. | 20.0 | c.c. |
| "Hypo" required | 20.0 | " | 20.1 | " | 20.1 | " | 20.0 | " | 20.2 | " |
Acetic acid, then, does not interfere to any serious extent.
Effect of Varying Sodium Acetate.—These experiments were like those last mentioned, but without acetic acid, and with varying amounts of sodium acetate.
| Sodium acetate added | 0 gram | 1 gram | 2 grams | 5 grams | 10 grams |
| "Hypo" required | 20.0 c.c. | 20.0 c.c. | 20.2 c.c. | 19.3 c.c. | 18.2 c.c. |