Brown — The Fatigue of Iron and Nickel Wires. 



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The wire was then taken down and heated as before once to a briijht 

 red heat ; it was cleaned, and its rigidity measured and found to be about 

 770 X 10* grams, per sq. cm. It was put into the solenoid and tested as 

 before; the results are shown in Table II. 



Table II. 

 Rigidity = 770 x 10'^ grammes per sq. cm. 



Tiie wire was again taken down out of the solenoid and heated once more 

 to a bright red heat, and when cleaned and tested the rigidity was found to 

 be about 750 x 10^ grammes per sq. em. It was once more put into the 

 solenoid and tested for fatigue, with the results shown in Table III. 



Table III. 

 Rigidity == 750 x 10° grammes per sq. cm. 



