Brown — Subsidence of Oscillations of Iron Wires and Alloys. 397 



In order, therefore, to test if this would hold with other loads, sets of 

 observations were made for both D.O. and A.C. magnetic fields when the 

 wire was loaded with 05, 30, and 4'36xl0* grammes per sq. cm. respec- 

 tively. A load higher than the last-mentioned could not be applied with 

 the present arrangement of apparatus, that is, applied in such a way as to 

 keep the radius of gyration of the vibrator constant. 



The results thus obtained along with the corresponding values from 

 Table II are given in Table III, and are shown as a curve in fig. 2 

 (p. 398). In Table III there are given the amplitudes of the first and 

 seventieth vibration only for both magnetic fields, and in the lower line 

 are the differences, in scale divisions, of the amplitudes of the oscillations 

 for the D.C. and A.C. fields for each load employed. 



Table III. 



In fig. 2, the abscissae represent the longitudinal loads on the wire, and the 

 ordinates the corresponding diiSerences mentioned above ; and it is seen that 

 the resultant curve when produced cuts the axis of abscissae at the point 

 corresponding to a load of about 5'7 x 10' grammes per sqcm. : which means 

 that if the wire were loaded to that amount, the D.O. and A.C. damping 

 curves would be identical. 



For loads still higher the iron wire would then behave in the same way as 

 a soft nickel wire, that is, the A.C. damping curve would lie above \he D.C. 

 curve. 



