166 



Scientific Proceedings, Royal Dublin Society. 



Section I. 

 Nickel wire. 



The wire was a No. 16 s.w.g. of simple rigidity 790 X 10 6 grammes per 

 sq. cm., the load on the lower end being Tox 10 5 grammes per sq. cm. The 

 magnetic field in the solenoid S corresponding to this load, that is, to give the 

 largest "Wiedemann effect," 1 was 20c.g.s. units, and the current through the 

 wire T was one ampere. The experiments were performed as explained above, 

 and the results are shown in Table I, where are also given for comparison 

 the results previously found for the same wire with longitudinal alternating 

 magnetic fields of the same intensity as the transverse alternating magnetic 

 fields now employed. 2 The letters d and F in the tables represent the 

 deflection or twist and the fatigue respectively. 



Table I. 



From the values in Table I it will be seen that the maximum fatigue due 

 to a transverse alternating magnetic field is about 8'5 per cent, less than that 

 due to a longitudinal alternating magnetic field, and that it takes about 



1 Scient. Proo. Roy. Dubl. Soc, vol. xiii (1911), No. 3, p. 31. 



2 Ibid., vol. xiv (1915), No. 26, p. 338. 



