70 ART. 4. — K. HONDA AND T. TERADA. 



or ar-ao = oa = . ^^^^ 



but since 



we have finally 





da E 1 fiE 



T dt E- dt 



Thus the effect of tension upon the coefficient of thermal expan- 

 sion can be found from the temperature coefiicient of the modulus 

 of elasticity. The relation was first obtained by Dahlander/-' and 

 verified by him to agree well with the experiment. In problems 

 which do not relate to magnetism, the hysteresis effect is generally 

 very small, so that tlie agreement might have been expected. 



*) Dahlander, Pogg. Ann. 145, p. 147, 1872, 



