Rutherford. — On Magnetic Viscosity. 



203 



The greater the radius of the cylinder the longer the 

 induction takes to decay. 



In this case the induction falls extremely rapidly, and in 

 about loioo o^ ^ second has fallen to half its original value. 

 The subsidence of the remainder is much more gradual. 



20 



30 



40 



Soft-iron and Steel Bings. 

 Curve 13 shows the fall of induction for soft-iron and steel 

 rings of sectional diameter 0-93cm. It will be observed that 

 the rate of decay of the induction is much slower when the 

 magnetic circuit is complete, as in the iron and steel rings, 

 than in short cylinders of metal. 



Summary of Results. 

 1. For finely-laminated iron, the lines of force pass out 

 into the secondary circuit very rapidly after the magnetizing 

 current is broken. It was experimentally shown that the 



