Brown — Mechanical Stress and Magnetisation of Iron. 487 



Table III. 



Fig. 3. — Magnetic field. 



If for the three different loads we plot the values of the lengths of 

 the wires as abscissae, and as ordinates the corresponding values of the 

 maximum twist when the wire was in a longitudinal magnetic field of 

 2'5 units, the points will be found to lie very approximately in a straight 

 line in each of the three cases, and each of these straight lines when 

 produced will pass tlirough the origin. These results show that the twist 

 of the free end of the wire is directly proportional to the length of the 



SCIENT. PEOC. E.D.S., VOL. XII., NO. XXXVl. 3 Z 



