OP FERROMAGNETIC WIRES BY MAGNETIZATION. 9 



6. Nickel. As will be seen from Fig. 6, tlie effect of tension 

 in weak fields is to diniinisli the contrnction due to niagnetiz- 

 afioii, and the amount of diminnfion increases, as the tension is 

 increased. Tn strong fields, the ct)ntrarv is tlic case. Fig, 7 shows 

 the relation hetween the chano'e of leno-th and the tension nnder a 

 constant field. Fnch of the curves has a minimuin ])oint except in 

 weak fields. As the field is increased, tlie minimum occurs hy greater 

 tension. 



Some of the results of measurement are sfiven in the f^llowin"' 



tabl( 



In Bidwell's experiment, the effect of londing less than 8.5 

 kilograms per scpiare millimeter was not studied ; but his gener.al 

 results agree with those of the present experiment. 



