In resumè twelve experimental lines of evidence are cited in favor of the adoption of the molecular group theory of the nature of liquids. This theory is assumed in the interpretation of results with octyl alcohols.

The following twenty-two octyl alcohols were used: octanol -1, -2, -3, -4, 2-methyl heptanol -1, -2, -3, -4, 3-methyl heptanol -1, -2, -3, -4, 4-methyl heptanol -1, -2, -3, -4, 5-methyl heptanol -1, -2, -3, 6-methyl heptanol -1, -2, -3.

The value of the effective diameter of the primary normal alcohols is approximately 4.5 A. With these octyl alcohols the increase for OH and C${\mathrm{H}}_3$ in a branch is approximately 0.0 A and 0.24 to 0.75 A respectively. When attached to the same carbon atom the increase caused thereby is not noticeable. These results are in fair agreement with previous similar measurements of isomers with other primary alcohols.

Two types of association were found. When the OH group is attached to the end or next to the end of the alcohol molecule, two of these molecules are associated end to end, the lengths of the chains being in the same straight line. On the other hand when the OH group is attached to any other carbon atom, the molecules are associated side by side. This is shown by the planar distances in the direction of the molecule which indicate in the first case the length of two molecules and in the second case the length of a single molecule.

• Received 15 January 1930

DOI:https://doi.org/10.1103/PhysRev.35.726