1. There exists a relation (Remark: Graphics omitted.) between orthobaric densities for normal and abnormal liquids. 2. By modifying the above equation, we obtain (Remark: Graphics omitted.) each side being proved to be a linear function of temperature. 3. For constants A and E it was found that A=32.3 (Remark: Graphics omitted.) and E=0.17 Vk for normal liquids. E is, therefore, an additive quantity if Vk is additive. 4. By dint of the relation for constants A and E mentioned above, we have a reduced equation (Remark: Graphics omitted.). 5. For lower temperatures, we have derived a vapour pressure equation. (Remark: Graphics omitted.).