The third paper of this series, Id described the use of the p-bromo ether synthesis of olefins in a systematic survey of the hexenes. Eleven of the thirteen possible hexenes had been prepared, two having been obtained in apparent cis-trans modifications. The same synthesis has now been used in a survey of the heptenes. Seventeen of the twenty-seven possible heptenes have been prepared, ten of this number being herein described for the first time. ...