what is the english of 振動週期 ?

Period of oscillation Each magnet being individually labeled was attached about the center to a thin fiber (DuPont, .20mm diameter, four lb. test leader material). In turn, each magnet was suspended from a rigid rod by approximately 15cm of fiber. When suspended by the fiber each magnet behaved very much like a compass needle. Regardless of the location, the magnets (if unperturbed) would remain aligned with the earth's magnetic field.
There was a concern regarding whether or not the magnetic field strength and direction in the laboratory was equivalent to the general local value being used in the calculations. The concern was that lab equipment or building wiring (or even the actual building) would dominate or at least effect the magnetic field strength in the lab or have the permanent ferromagnets being attracted to objects within the laboratory setting. Without a magnetometer to properly measure the filed strength in the lab, we assumed that if this was true, the magnetic field would not be uniform within the lab. That is, proximity to walls or other equipment would generate different period measurements. Trial period measurements at several locations within the lab confirmed the non-uniformity of the local magnetic field. Therefore, the period measurement apparatus was moved outdoors away from any building and any obvious power or communication lines. However, there is no guarantee that the measurements were performed away from any unnatural subsurface source of a magnetic field.
Outdoors, the suspended magnets were enclosed in a cardboard container in order to reduce and wind. The magnets were disturbed slightly from equilibrium to begin the oscillations. The total time for twenty oscillations was measured for each magnet; with the exception that forty oscillations were measured for magnet number one. One observer counted the number of oscillations while the other used a stopwatch to measure the total time. The process was repeated five times for each magnet. The average period was either 1.5 or 1.4 seconds for each magnet. Statistical treatment of error indicates an accuracy of approximately 1%. Thus, even without further calculations, it was evident that the dipole moments of each magnet were very nearly the same. The results of the period measurements are listed in table two.

振動週期 = Period of oscillation

that is the time required for an entire oscillation

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