1904.] Thermoelectric Power 'produced by Magnetisation. 



427 



Table II. 



P = tractive force. E = elongation. 



H. 



P. 



P/200. 



E. 



P/200 + E. 



40 



6,550 



33 -0 



12 -0 



45 -0 



50 



7,000 



35*0 



20 -0 



55 -0 



70 



7,700 



38-5 



24 -0 



62 -5 



i nr> 



1UU 



o,uuu 





■CO u 



DO 



150 



9,500 



47 -5 



17-0 



64 -5 



200 



10,250 



51-0 



10 -o 



61 -0 



300 



11,100 



55-5 



- 2-5 



53 



400 



11,600 



58 -0 



-15-0 



43 -0 



500 



12,200 



61 -0 



-27 -0 



34-0 



600 



12,700 



63 -5 



-35 -0 



28 -5 



700 



13,200 



66 -0 



-40 -0 



26-0 



800 



13,700 



68 -5 



-44 -0 



24 -5 



curves can hardly be the result of accident, the less so as the same 

 similarity is manifested under different conditions. 



Tension has the effect of lowering the elongation curve of iron, the 

 maximum becoming smaller and contraction beginning at an earlier 

 stage of the magnetisation. If the tension is great there is no 

 preliminary elongation at all, and the wire begins to contract with the 

 smallest magnetising forces. Curves (e) and (/), fig. 5,* show the 



3fto-~__ 400 Magnetic held. 



(if 



Fig-. 5. — Curve (G-) shows changes of thermoelectric force for an unstressed iron 

 wire; (F) same when the wire was loaded with 1620 kilogrammes per sq. cm. 

 Curves (e) and (/) show changes of length for iron loaded with 351 and 

 1600 kilogrammes. Crosses on (F) and (G-) indicate (e) and (/) corrected 

 for mechanical stress. 



* ' Koy. Soc. Proc.,' vol. 47, p. 474, fig. 2, 1890. 



