1. Determine the aniline point of petroleum products and solvents, when they are lower than the boiling point and higher than the solidification point of the aniline-sample mixture and, furthermore, the aniline-heptane point when it is lower than the crystallization temperature of the aniline in the aniline-sample mixture. 1.1 The aniline-heptane points differ from those determined on the same products using gasoline as diluents with aniline points of 60 °C and are, in general, a few degrees higher than the latter. These differences depend both on the nature of the product tested and the diluent used.