Brown — 3Iechamcal Stress and 3£agneHsation of Iron. 495 



Five of these wires of different sizes were taken and put through the tests, 

 with a load on the end of each wire equivalent to 10° grammes per sq. cm. ; 

 and the twist of the free end measured when each wire was placed successively 

 in twelve different longitudinal magnetic fields. In every case the current 

 density in the wire was 100 amps, per sq. cm. 



The three thicker wires were tested for simple rigidity, and the mean 

 value obtained was 815 x 10'^ grammes per sq. cm., which falls about the 

 position H2.5 in our arbitrary scale of temper. 



The results obtained are shown here in Table VIII., and as curves in fig. 6. 



Table VIII. 



Fie. 6.— Magnetic field. 

 SCIEIS'T. PEOC. S.D.S . TOL. XII., NO. XSXTJ. 



