TransactionsPublished under the care of the General Secretary and the Treasurer . ge on the effect of high temperatures is still wanting. On comparing the results in soft iron, tungsten steel, cast andannealed cobalts, we notice the remarkable fact that the changesof length by magnetization of these metals are, at ordinary tem-perature, so very different from each other, but assume, at snffi-ciently high temperatures, an extraordinary simple character; theythen tend to become proportional to the magnetizing force. Hysteresis accompanying the change of length by magnetization.— The hysteresis i
TransactionsPublished under the care of the General Secretary and the Treasurer . ge on the effect of high temperatures is still wanting. On comparing the results in soft iron, tungsten steel, cast andannealed cobalts, we notice the remarkable fact that the changesof length by magnetization of these metals are, at ordinary tem-perature, so very different from each other, but assume, at snffi-ciently high temperatures, an extraordinary simple character; theythen tend to become proportional to the magnetizing force. Hysteresis accompanying the change of length by magnetization.— The hysteresis is of a very complex character; graphically rep-resented, the curve of hysteresis is symmetrical about the line of 350 KAGAOKA: MAGXETOSTEICTION. zero magnetizing force, and presents four loops during a completemagnetic cycle. Ehoads^ found remarkable coincidence of hysteresisir thermoelectric power of magnetized iron with that due to elon-gation by magnetization. The accompanying diagram will clearlyillustrate the nature of hysteresis. Hysteresis In the length change of iron. Uoo Fig. 4. 2. Change of YoLUirE by. Magnetization. Joule showed that there is no change of volume by magnetization;Cantone was the first to notice a slight change of volume in change in the internal volume of ferromagnetic tubes wasobserved by Knott; Bidwell showed indirectly with iron ringsthat the volume change must exist. On experimenting with iron,nickel, and nickel steel ovoids, I, with Mr. Honda, found that thechange of volume, though very small, may ultimately become tol-erably large in strong fields, so that the motion of capillary menis-cus of a dilatometer can sometimes be followed by the naked experimenting with the volumenometer, extreme care is neces-sary to place the ovoid axially in the magnetizing coil, and to keepit free from the wall of the dilatometer tube. Non-uniformity ofthe field may become another source of error which has often beenneglected. Although the magne
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Keywords: ., bookcentury1900, bookdecade1900, bookidtr, booksubjectelectricity
