At a recent meeting of the Society, Dr Crum Brown exhibited a gutta percha bottle of irregular form, which, when applied as a resonance cavity to reeds of various pitches, gave very good imitations of certain vowel sounds. By closing certain apertures in the side of the bottle it could be made to say A (“father”), A (“awe”), O (“oh”), and I (“machine”). When the cavity was kept constant, and the pitch of the reed was altered, the same vowel continued to be given. Dr Crum Brown was good enough to lend us the apparatus, in order that we might investigate the sounds given by the bottle in the same way as we have been investigating certain human vowel sounds, by obtaining and magnifying phonographic traces, and then subjecting them to harmonic analysis as far as the sixth partial tone.