of Steel, JSfickel, Cobalt, and iSickel-Steels. 



63 



fields, however, the twist does not continue to increase with 

 the circular, but we notice a maximum as will be clear in the 



Fig. 12. 



Fig. 13. 



figure (see fig. 13). There is great experimental difficulty in 

 increasing the circular field, inasmuch as the wire becomes 

 heated and the result is materially affected. 



