48 Scientific Proceedings, Royal Dublin Society. 



wire in both the liard nnd soft states, when tliere wns no field round the wire, 

 and when there was a magnetic field of 25 nnits round it. 



The extraordinary effect of annealing will be seen from the behaviour of 

 tlie No. 16 wire in the two states : in the hard state the final amplitude in 

 a magnetic field of 25 units was only 3-^ per cent, smaller than in no field, 

 whereas in tlie soft state the decrease in tlie amplitude is over 57 per cent., 

 and this is produced by a decrease of about 8 \iq\: cent, in the rigidity. 



1 am indebted to Mr. F. W. Warwick, d.a., b.k., of tlie Pliysics 

 Laboratory in this college, lor assistance in tlic observations and drawing of 

 tlie curves in the latter part of this x>ai)er. 



