. Studies in physics. describedlater. During the experiments the load, the length of wire and themoment of inertia of the pendulum were always the same. It is seenthat the maximum variation in period is about seconds or a varia-tion of 16 per cent. The significance of such a wide variation in theperiods of torsional vibrations is very evident. It is also highly probablethat the variation is too complicated to be corrected for, in any apparatusin which these suspensions are used. The Effect of Drawing.—It was soon found that each state was quitestable in itself and unless the wires were su
. Studies in physics. describedlater. During the experiments the load, the length of wire and themoment of inertia of the pendulum were always the same. It is seenthat the maximum variation in period is about seconds or a varia-tion of 16 per cent. The significance of such a wide variation in theperiods of torsional vibrations is very evident. It is also highly probablethat the variation is too complicated to be corrected for, in any apparatusin which these suspensions are used. The Effect of Drawing.—It was soon found that each state was quitestable in itself and unless the wires were subjected to vigorous treat-ment, the curves for a given sample of wire were always of a definitetype. This was especially true of states II. and III. This discoverymade it possible to study more carefully, each state. When the work was undertaken, it was thought desirable to note theeffect of drawing on the wires. A sample of each of the seven smallestof the wires was tested, and period-amplitude curves were 5* IC AMPLITUDE. Fig. 2. w l\ 0 «OH «o w • Js*^ O 4 Ta~---^i^k__J 10°AMPLITUDE. Fig. 3. 150 20° Fig. 2 shows these curves reduced to a common period at a chosen ampli-tude. The wires are arbitrarily numbered, in general inversely as thesuccession of the drawings. The diameters are given in the table below. Wire No. 1 234567 Diameter. .100 mm. .114 .133 .145 .165 .181 .206 There is seen a tendency for the effect to become more and more markedas the diameter of the wire is drawn smaller. The same effect is bettershown in Fig. 3 which represents the curves for the four smallest wires 468 ARNOLD J. OEHLER. [Ier?™ when these wires were thrown into state III. Here, as in Fig. 2, thecurves have all been reduced to a common period at a certain explanation of this has been offered by Sieg,1 who observed the sameeffect in platinum-iridium wires. States II. and III.—The bringing about of certain states in the wireswas at first very difficult, because
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