According to Bose and Bose² tambulin should be 3∶8∶4′-trimethyl-ether of herbacetin. A compound of this constitution has now been synthesised from 3∶4′-dimethyl-ether of kaempferol. Its properties differ markedly from those of tambulin. The constitution of the latter should therefore be considered as still unsettled. The nature of the synthetic substance has been confirmed by preparing its diethyl-ether and proving its identity with 3∶8∶4′-trimethyl-5∶7-diethyl-ether of herbacetin prepared by an independent method.