A Magnetostriction Oscillator Producing Intense Audible Sound and Some Effects Obtained

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Abstract
Apparatus is developed capable of pushing the magnetostrictive oscillation of nickel to the limit set by its mechanical strength. The intense audible sound produced is introduced under water from beneath the surface, continuous operation of the vibrator being secured by spray cooling. The interiors of corks are charred to cinder by the sound. A fountain 6 cm high forms on the surface of water, and is proved to be due to pumping action of the reciprocating rod and not to radiation pressure. Erosion of metals and of glass by cavitation and resultant water hammer is obtained. Colloids of oil and of carbon in water are produced. Curious fatigue effects in glass are observed. Whitened appearance and erratic motions of air bubbles released in water in the presence of the sound are observed, and theory is developed to explain these and the ``atomization'' of liquids. Flattening of a drop of liquid against a vibrator is observed and attributed to sonic attraction and to the reaction of sonic radiation. Frogs, fish, larvae, and water fleas are killed by the sound. Bacteria are killed so quickly that partial sterilization of milk in continuous process is effected. Striations in a Kundt tube that are parallel to its axis are produced, and an explanatory theory developed.

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