170 



Dr. M. Maclean. On the Effects of 



§10. It will be noticed that the current is from unstretched to 

 stretched, through the hot junction for three specimens of copper, and 

 from stretched to unstretched through the hot junction for other three 

 specimens. The probable explanation of these results is suggested in 

 §§13,14,15. 



Table IV. 



Condition of 



conductor. 

 Current from 



1 to <u 



through the 

 hot junction. 



Per- 

 centage 

 perma- 

 nent 

 elonga- 

 tion. 



Current 



in 

 mikro- 

 ampere 



per 

 degree 

 up to 

 100° C. 



XyjXiai. 



resist- 

 ance in 

 circuit 

 in ohms. 



Thermo- 

 electric 

 difference in 

 mikrovolt 

 per degree 

 centigrade 

 difference of 

 temperature. 



1 stretched 



2 unstretched 



\ 1-0 





J. Ol. t 





1 stretched 



2 unstretched 





'003 



X OXtJ 





1 stretched 



2 unstretched 



1. 1-5 



U J. 







1 unstretched 



2 stretched 



\ 0-7 

 J 



-0018 



1-519 



0-0027 



1 unstretched 



2 stretched 





0-005 



1-531 



0-0077 



1 unstretched 



2 stretched 



}- 



0-0024 



1-518 



0-0036 



1 unstretched 



2 stretched 



1 20 -0 

 J 



0-0174 



1 -52 



0-0264 



1 unstretched 



2 stretched 



1 2-0 



0-009 



2-312 



-0208 



1 stretched 



2 unstretched 



}- 



0-047 



1-937 



-0910 



1 stretched 



2 unstretched 



1 0-5 



0-056 



1-835 



0-1027 



1 stretched 



2 unstretched 



1 0-5 



0-036 



1-924 



-0693 



1 stretched 



2 unstretched 



}- 



0*0135 



1-51 



-0204 



1 unstretched 



2 stretched 



1 0-7 



0-084 



1-596 



0-1341 



Conductor. 



Messrs. Johnson and 

 Matthey : — 

 (a) Copper, elec- f 

 trotype \ 

 (h) Copper, for J 

 alloy \ 

 (c) Copper, com- T 

 mercial {. 

 Messrs. Grlover : — 



(a) Copper, hard ^ 



(6) Copper, soft | 



Copper, labora- J 

 tory \ 



{ 



Reosfcene -| 



Platinoid -| 



German silver . . -j^ 



Manganin -j^ 



Aluminium . . . . 

 Nickel ........ I 



C. — Thermo-electric difference between free ivires and wires under stress, 

 producing (1) temporary elongation, (2) permanent elongation 

 (§§ 11-18). 



§ 11, The arrangements shown diagrammatically in fig. 3 were now 

 made to determine the thermo-electric difference between free wires 

 and wires while (c*) under stress, stretching them within their limits of 

 elasticity, and {b) under stress, stretching them beyond their limits of elas- 



