30 



Scientific Procee<lings, lioyal Dublin Societij.. 



thus: — The maximum electric current (100 amperes per square centimetre) 

 was sent througli tlie wire, and tlie twist or steady deflection read off on the 



Tab],e I. 



millimetre scale; tlie current was then diminished by steps, and the deflection 

 on the scale observed for each step, down to zero current, when tlie remanent 



