Page:Proceedings of the Royal Society of London Vol 60.djvu/460

428 Resistivity of Bismuth. Transversely Magnetised at —185° C. Strength of field Yolume resistivity in (C.G.S. units). C.Gr.S. units.

0 41,000 1,375 103,300 2,750 191,500 8,800 738,000 14,150 1,730,000 21,800 6,190,000

Hartman and Braun's Pure Electrolytic Bismuth. Resistivity of Bismuth Transversely Magnetised at —203° C. Strength of field (C.Gr.S. units). 0 ' 2,450 Yolume resistivity in C.GLS. units. 34,300 283,500 Electrical Resistivity of Bismuth in C.G.S. units, transversely magnetised in a Constant Magnetic Field, hut at variable Temperatures.

Temperature of the bismuth, wire. Out of the magnetic field. In the magnetic field. Strength 2450 C.G.S. units. Strength 5500 C.G.S. units. Strength 14,200 C.GLS. units. + 19° C. - 79 „ -1 8 5 ,, . -2 0 3 „ 116,200 78.300 41,000 34.300 123.500 105.000 186.000 283.500 132.000 158.000 419.000 187,000 284,000 1,740,000

It will be seen that the observations lead to the following conclusions. If the transverse field is zero, then cooling the bismuth always reduces its resistance. If then the bismuth is transversely magnetised, the resistance is increased, and for every temperature below the normal one (about 20° C.), there is some particular strength of transverse field, which just annuls the effect of the cooling, and brings the resistance of the bismuth back again to the same value it had when not cooled, and not in any magnetic field. Hence the curves showing the resistance at any temperature lower than the normal one (20° C.) as a function of the transverse field, cross the curve showing the resistance as a function of the field when taken at the normal temperature. These crossing points are, however, not identical for