WIEDEMANN EFFECT IN FERROMAGNETIC SUBSTANCES. 



We tested 8 different samples shown in the following tahle : 



Our arrangement for studying the Wiedemann effect in nickel 

 steel wires was the same as that used by Professor Nagaoka and one 

 of our members in the experiment described in the paper above 

 referred to. 



To the extremities of a nickel steel wire 21cm. long were brazed 

 stout brass wires, and a light mirror was attached to the lower brass 

 wdre. The upper wire was clamped to a small tripod, wdiich rested 

 on the top of a magnetizing coil provided with hole, slot, and plane 

 arrangfement. One end of the accumulator was connected with the 

 tripod, while the other was led to the mercury pool i)laced under the 

 suspended wire. The wire hung vertically in the axial line of the 

 coil, which was 30cm. long :ind gave a field of 37.97 C.G.S. units at 

 the center by passing a current of one ampere. The vertical compo- 

 nent of the terrestrial magnetic field was compensated by placing 

 another coil in the interior of the magnetizing coil. The twist was 

 measured by scale and telescope, by which a torsion of 0.2" per cm. 

 w^as easilv read. 



