Change of electrical resistance in a magnetic field : with experiments on the change of resistance of electrolytes . circulating in the molecules. Though Tomllnsons results are of unquestioned accuracy,they are of little value for theoretical purposes. It is difficultif not impossible to estimate accurately the strengths of the fieldsused, but they were probably quite weak. This conclusion is justi-fied by his statement that a field of considerable strength was480 times the earths field - probably not over 100 lines persquare centimeter at best. The work of Goldhammer ( Wied. Ann. Vol. XXXI, p
Change of electrical resistance in a magnetic field : with experiments on the change of resistance of electrolytes . circulating in the molecules. Though Tomllnsons results are of unquestioned accuracy,they are of little value for theoretical purposes. It is difficultif not impossible to estimate accurately the strengths of the fieldsused, but they were probably quite weak. This conclusion is justi-fied by his statement that a field of considerable strength was480 times the earths field - probably not over 100 lines persquare centimeter at best. The work of Goldhammer ( Wied. Ann. Vol. XXXI, p. 360,1887.) deals with other metals besides iron, cobalt, and nickel,and hence is of considerable interest. In order to avoid anymechanical deformations due to magnetization, he worked with filmsdeposited electrolytically upon glass. The resistances were meas-ured by the Wheatstones Bridge method. To increase the sensi-tiveness, a second slide wire was used , as shown in Figure increased the sensitiveness 113 fold but did not increase theabsolute accuracy of the apparatus. He claims an accuracy of - 6 -. .005 ^ to .01 %m Bismuth, tellurium,antimony, cobalt, nickel, andiron were tested with both transverse and longitudinal magnetiz-ation. The fields were obtain-ed from a large each case the length of theair-gap and the strength of themagnetizing current are speci- fied, but the actual strength of the magnetic field is not given. The following table is compiled as representative of his results. Metal Thickness Resistance Per cent change in Resistance longitudinal transverseBismuth . Tellurium Antimony Experiments were made with bismuth, having the field atvarious angles from 0° to 90° with the lines of flow. These showedthat the change in the effect varied continuously with the anglebetween the lines of field and the lines of flow. These resultshe represents graphically as shown in F
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