1.1 ,This standard is for use in calculating the weight and volume of benzene, toluene, mixed xylenes, styrene, ortho-xylene, meta-xylene, para-xylene, cumene, ethylbenzene, 148.9 to 176.7°,C and 176.7 to 204.4°,C aromatic hydrocarbons, and cyclohexane. A method is given for calculating the volume at 15°,C and 20°,C from an observed volume at t°,C. Table 1 lists the density in Vacuo at 60°,F for chemicals used to develop the relationship. Densities (or weights) “,in vacuo”, represent the true density (or weight) if measured in a vacuum without the buoyancy effect of air acting on the liquid. It is representative of the actual amount of product present. Densities (or weights) “,in air”, represent what would actually be measured on a scale. The difference is on the order of 0.13 ,%. Modern densitometers measure density in vacuo and the ASTM recommends the use of in vacuo densities (or weights).