Letter from John Edward Lennard-Jones, regarding three papers 'Polar structures in the theory of conjugated molecules I. Identification of the ethylene p-electron states', 'Polar structures in the theory of conjugated molecules. II. Symmetry properties and matrix elements for polar structures' and 'Polar structures in the theory of conjugated molecules III. The energy levels of benzene' by David Parker Craig Sectional Committee: Chemistry The amended papers meet the criticisms of his reports, and are now suitable for publication. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on recto as received 8 June 1949. 6 June 1949