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A study was made of crystallite orientation in cubic ferrites when pressed in a magnetic field. One easy axis orients in the field direction, the other easy axes lying at random in or near a perpendicular plane. Experimental torque curves have the theoretically predicted shape. The magnetic field required for microwave resonance is lower than in the same nonoriented ferrite if the axis of alignment and the field are parallel. This occurs because the anisotropy field Ha is no longer randomly oriented but helps to supply part of the resonant field requirement. Values of saturation magnetization (Ms), anisotropy energy (K), and resonant field (Hr) at 14 775 mc/sec were measured on a series of oriented polycrystalline nickel cobalt ferrites. Values of the measured resonant field are compared with values obtained from Kittel's resonance relation using the independently measured values of Ms and K.

A laser interferometer for earth strain measurements has been constructed and is described. The apparatus is designed to measure displacements down to small fractions of the laser wavelength. Measurements of length change of the interferometer arm of 10 m length were obtained during normal microseismic activity and following a distant earthquake. Some representative results of this laser application are presented.

The possibility of using a laser interferometer as a geophysical strainmeter was examined. A thermally stabilized laser was used and the results compared with a quartz Benioff strainmeter. From these measurements both long‐ and short‐term stability of the laser radiation were calculated. The results indicate that the long‐term stability is sufficient to observe earth tides while the short‐term stability is better than 1:1010.

A technique is described for the automatic measurement of ultrasonic velocity changes in continuous wave experiments. An oscillator is locked to a mechanical resonance of the sample. Velocity changes appear as frequency changes of the oscillator and are easily recorded. Some typical results are given.