The results given by Paalzow are as follow:—
| Mixtures of Sulphuric Acid and Water. | |||
| Temp. | Resistance compared with mercury. | ||
| H₂SO₄ | 15°C | 96950 | |
| H₂SO₄ | + 14 H²O | 19°C | 14157 |
| H₂SO₄ | + 13 H²O | 22°C | 13310 |
| H₂SO₄ | + 499 H²O | 22°C | 184773 |
| Sulphate of Zinc and Water. | |||
| ZnSO₄ | + 23 H²O | 23°C | 194400 |
| ZnSO₄ | + 24 H²O | 23°C | 191000 |
| ZnSO₄ | + 105 H²O | 23°C | 354000 |
| Sulphate of Copper and Water. | |||
| CuSO₄ | + 45 H²O | 22°C | 202410 |
| CuSO₄ | + 105 H²O | 22°C | 339341 |
| Sulphate of Magnesium and Water. | |||
| MgSO₄ | + 34 H²O | 22°C | 199180 |
| MgSO₄ | + 107 H²O | 22°C | 324600 |
| Hydrochloric Acid and Water. | |||
| HCl | + 15 H²O | 23°C | 13626 |
| HCl | + 500 H²O | 23°C | 86679 |
365.] MM. F. Kohlrausch and W. A. Nippoldt[1] have determined the resistance of mixtures of sulphuric acid and water. They used alternating magneto-electric currents, the electromotive force of which varied from 12 to 174 of that of a Grove's cell, and by means of a thermoelectric copper-iron pair they reduced the electromotive force to 1429000 of that of a Grove's cell. They found that Ohm's law was applicable to this electrolyte throughout the range of these electromotive forces.
The resistance is a minimum in a mixture containing about one-third of sulphuric acid.
The resistance of electrolytes diminishes as the temperature increases. The percentage increment of conductivity for a rise of 1°C is given in the following table.
- ↑ Pogg., Ann. cxxxviii, p. 286, Oct. 1869.
