ON TRANSIENT ELECTRIC CURRENTS. 359 



magnetizing 1 force is not great. In all cases, the maximum transient 

 current is greater as the wire becomes thicker. Thus increasing the 

 diameter of the wire has. to some extent, a similar effect to that pro- 

 duced by increasing the twist in a wire of the same diameter. 



When we examine the variation of the maximum position, we 

 notice another feature analogous to that produced by increasing the 

 an fie of twist in the same wire. As the diameter of the wu're 

 increases, the maximum point is shifted into stronger fields. The 

 following table gives the magnetizing force corresponding to the 

 maximum transient current in wires of different thickness. 



For r-0.44 £ 14, g 



., r=0.62 £ = 16, 



„ »—0.77 £=22, 



„ r = 1.00 £=30. 



The wires used in the above experiment were of ordinary soft 

 iron. If the quality of iron be different, the transient current curve 

 is somewhat changed. Thus, with a wire of 0.91 mm. radius 

 specially drawn from Swedish iron, the transient current was greater 

 than that obtained with the thickest wire used in the above experiment. 

 The course of the curve is shown in Curve V. Fig. Y. In addition to 

 this, the maximum position corresponds to a weaker magnetizing field 

 than it would have done had the wire been of ordinary soft iron. 

 The general feature of the curve, however, does not seem to be 

 greatly affected by the difference in quality. 



Another set of experiments was performed by varying the angle 

 of twist while the reversing field w r as kept constant in magnitude. 

 The wires were taken from the same specimens as used in the above 

 experiments. The magnetizing force was in all cases equal to 19.7. 

 The following table gives the readings, which are plotted in Fig. VI. 



