642 Influence of Stress on Electrical Conductivity of Metals 

 The following readings were taken : — 



Tension in 

 grammes /mm. 2 



Change of 

 Resistance, 



f.xo, 



Change per 

 gramme / mm. 2 



1-88 



'102 

 •99 

 1-95 

 5-08 

 7-05 

 1011 

 15-16 

 19-95 

 24-9 

 29-8 



•054 

 •053 

 •052 



•054 



•053 



•0537 



•0537 



•0530 



•0529 



•0528 



18-8 



376 



94-05 



1316 



188-8 



2821 



376-0 



4702 



564-3 





The resistance of bismuth is decreased by tension, the mean 

 value of the decrease being : — 



dK ^ko- -.^ a gramme 



-=- = -053o . 10- 4 per s ^-. 



B, r mm/ 



Summary of Residts. 



Metal. 



Pressure. 



Change of 



Resistance, 



£•* 



per atmosphere. 



Tension. 



-=- . 10 4 per 

 R 



gramme /mm. 2 



Lead 



Aluminium 



Bismuth 



-143 

 - 38-5 

 +197 



+ 22-2 



-•535 



Manganin 





Of the substances investigated in the present experiments, 

 two, manganin and lead, have been investigated both by 

 Lissell and Lussana. The present results are in very good 

 agreement with those obtained by Lissell, showing consider- 

 able differences from those of Lussana, thus : — 



