A pure geometrical isomer of 1, 3, 5-heptatriene (1-methyl-l13, 5-hexatriene), one of the four possible isomers, has been reported earlier. 2 This isomer was obtained by catalytic dehydration over alumina of 3, 5-heptadien-2-01. A different synthesis of 1, 3, 5-heptatriene, now reported, was examined in order to establish the validity of the method of Hwa, de Ben-
