Other physical properties of these solutions, such as density, colour, optical rotatory power, &c., like the **conductivities**, are additive, i.e.

The electrical **conductivities** of normal solutions of the acids have been tabulated.

Its coefficient of linear expansion between 0° and 100° is 0.002717; its specific heat 0.0562; its thermal and electrical **conductivities** are 145 to 152 and '14.5 to 140.

The following table gives the electric **conductivities** of a number of metals as determined by Matthiesen, and the relative internal thermal **conductivities** of (nominally) the same metals as determined by Wiedemann and Franz, with rods about 5 mm.

On mixing dilute solutions of the diazonium hydroxide and the alkali together, it is found that the molecular **conductivity** of the mixture is much less than the sum of the two electrical **conductivities** of the solutions separately, from which it follows that a portion of the ions present have changed to the non-ionized condition.

The **conductivities** of thin slices of crystals have been measured by C. H.

Neglecting the external heat-loss, and the variation of the thermal and electric **conductivities** k and k', we obtain, as before, for the difference of temperature between the centre and ends, the equation O, Tho z Go = C 2 R1/8qk = ECl/8qk = E 2 k'/8k, (11) where E is the difference of electric potential between the ends.

Edin., 1867-68), Tait was led to the conclusion that " the thermal and electric **conductivities** of metals varied inversely as the absolute temperature, and that the specific heat of electricity was directly proportional to the same."