1. The constant B, the effective molecular volume, is additive. 2. The respective constant in the volume and temperature relations becomes independent of the nature of the substance when it is expressed in reduced form. 3. From the volume and temperature relations of the molecular fluidity the reduced equations of the following form have been obtained. (Remark: Graphics omitted.)
(1) Tautomeric transformations may occur when the neutral solution of these tolueneazo-cresols change into the alkaline. (2) The dilute neutral solution of these compounds is generally yellow and becomes deep yellow or orange when the solution is alkaline. (3) We can respectively give A(azo)- and R(red)-forms to these tautomers. (4) There is one absorption band when hydroxyl-group in cresol ring takes para-position with regard to the azo-group, and two bands when ortho-position. (5) The methyl-group has a hyperchromic influence, but when added to an already methylated compound, it ceases to be effective in the absorption curve. (6) So far as the present studies are concerned, the methyl-group does not specially represent its influence with regard to the position.