The magnetization of cobalt as a function of the temperature and the determination of its intrinsic magnetic field . field was also measured with a magnet-ic balance made by Weber in Zurich and practically identical with op the one described by Weiss141. The results obtained by the twomethods were in close agreement. For convenience, the value ofthe field for currents from 2 to 25 amperes was determined by stepsof two or three amperes. From these data, curves were plottedgiving H as a function of the current. Copies of these curvesare given in Figure 2. The curves actually used in the calcula-
The magnetization of cobalt as a function of the temperature and the determination of its intrinsic magnetic field . field was also measured with a magnet-ic balance made by Weber in Zurich and practically identical with op the one described by Weiss141. The results obtained by the twomethods were in close agreement. For convenience, the value ofthe field for currents from 2 to 25 amperes was determined by stepsof two or three amperes. From these data, curves were plottedgiving H as a function of the current. Copies of these curvesare given in Figure 2. The curves actually used in the calcula-tions were plotted to such a scale that 1 cm. was equivalent to100 or 200 lines per square centimetor* Galvanometer. The galvanometer used was a Leeds andNorthrup type H instrument. It had a resistance of ohms, aballistic sensibility of mm. per microcoulomb on open circuitwith a scale distance of 50 cm., and a period of seconds on 22. Journal de Physique, j$6, pp. 432-435. (1907). See also:- T^Eclairage Electrique, 24, pp. 257-266. (1900). Journal de Physique, 29, pp. 3&3-390, (1900). - 14 -. - 15 - open circuit. The scale used had 500 divisions in a length of25 cm. and was made by photography from a very accurate 50 The telescope and scale were placed at a distance of2#0 cm.,approximately, from the galvanometer. At this distance,with the finer scale, the sensitiveness was increased about tenfold. With this arrangement, the throw could be read accuratelyto of a scale division or even less. As the Instrument asused was on closed circuit, it was practically aperiodic, and itssensitiveness was considerably reduced. Heating Apparatus. The induction helix was used as thecore around which was built up a small electric furnace to givethe necessary temperatures. For various reasons, two separatepieces of apparatus were built, one for the lower temperatures,the other for the higher temperatures. Up to 550°C the apparatus shown in section in Figure 3was used
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