The London, Edinburgh and Dublin philosophical magazine and journal of science . is one accompanying magnetiza-tion by an intermittent or alternate current of a definitefrequency, or one produced when the above-mentioned currentis passed directly through the substance. The sound isprobably caused by the continuous series of vibrations abovereferred to. The experiments of Beatson and others willagree with this view. De la Rive and Wiedemann ascribe the phenomenon tothe molecular effect, but Wertheim and Bachmetjew to themagnetic change in length. We also consider it highlyprobable that the chan
The London, Edinburgh and Dublin philosophical magazine and journal of science . is one accompanying magnetiza-tion by an intermittent or alternate current of a definitefrequency, or one produced when the above-mentioned currentis passed directly through the substance. The sound isprobably caused by the continuous series of vibrations abovereferred to. The experiments of Beatson and others willagree with this view. De la Rive and Wiedemann ascribe the phenomenon tothe molecular effect, but Wertheim and Bachmetjew to themagnetic change in length. We also consider it highlyprobable that the change of length is the cause producing thesound belonging to the second and third categories. Thepresent experiment was undertaken to get a clearer insightinto the nature of the phenomenon. In all previous experiments, the range of the frequency ofan intermittent or alternate current was very limited ; but inour case, a string alternator * was introduced for continuouslyvarying the period of the current. The arrangement isshown in fig. 1. A copper wire is horizontally stretched;. one of the ends is fixed to a support S, while the otherpassing over the pulley P is attached to a weight Q. Thewire is electrically insulated at the centre R, so that thecurrent through the two mercury cups rax and m2 flows inthe circuit C. The battery currents pass through the twomercury contacts M2 and M2. The vibration of the string is * K. Honda and S. Shimizu, Amer. Journ. Sci. vol. x. p. 64 (1900) jPhys. Zeitsch. 2 Jahrgang, vol. xxv. p. 371 (1901). 648 Messrs. K. Honda and S. Shimizu on the Vibration of maintained constantly oscillating by the electromagnet nand s. If the string is set in vibration with a single node at R,an alternate current is produced in the circuit C ; if only oneset of batteries is used, an intermittent current is producedin tbe same circuit. The frequency of alternation or of inter-ruption can easily be varied by the change of length and oftension of the wire. Cx and C2 are
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