The resistivity of liquids is, generally speaking, much higher than that of any metals, metallic alloys or non-metallic conductors. Thus fused lead chloride, one of the best conducting liquids, has a resistivity in its fused condition of 0.376 ohm per centimetre-cube, or 376,000 microhms per centimetre-cube, whereas that of metallic alloys only in few cases exceeds 100 microhms per centimetre-cube. The resistivity of solutions of metallic salts also varies very largely with the proportion of the diluent or solvent, and in some instances, as in the aqueous solutions of mineral acids; there is a maximum conductivity corresponding to a certain dilution. The resistivity of many liquids, such as alcohol, ether, benzene and pure water, is so high, in other words, their conductivity is so small, that they are practically insulators, and the resistivity can only be appropriately expressed in megohms per centimetre-cube. In Table VII. are given the names of a few of these badly-conducting liquids, with the values of their volume-resistivity in megohms per centimetre-cube:-- TABLE VII.--_Electric Volume-Resistivity of Various Badly-Conducting Liquids in Megohms per Centimetre-cube._ +---------------------------+----------------+---------------------+ | | Resistivity | | | Substance. | in Megohms | Observer. | | | per c.c. | | +---------------------------+----------------+---------------------+ | Ethyl alcohol | 0.5 | Pfeiffer. | | Ethyl ether | 1.175 to 3.760 | W. Kohlrausch. | | Benzene | 4.700 | | | Absolutely pure water | 25.0 at 18° C. | Value estimated | | approximates probably to | | by F. Kohlrausch | | | | and A. Heydweiler. | | All very dilute aqueous | 1.00 at 18° C. | From results by | | salt solutions having a | | F. Kohlrausch | | concentration of about | | and others. | | 0.00001 of an equivalent | | | | gramme molecule[10] per | | | | litre approximate to | | | +---------------------------+----------------+---------------------+ The resistivity of all those substances which are generally called dielectrics or insulators is also so high that it can only be appropriately expressed in millions of megohms per centimetre-cube, or in megohms per quadrant-cube, the quadrant being a cube the side of which is 10^9 cms. (see Table VIII.).