1907-8.] Young’s Modulus under an Electric Current. 675 
the two phenomena, but only a general connection, due to a certain 
similarity of conditions. In both cases a load is put on which alters the 
internal molecular state, and the wire tends to set into a new arrangement 
of molecular equilibrium. Variation of field in the one case, variation of 
temperature in the other, alters this state of equilibrium, and produces 
corresponding effects on the intensity in the one case, and on Young’s 
modulus in the other. Now, it may be that increase of temperature at 
first enables the molecules to set into more stable arrangements under the 
load, and therefore to increase the modulus. Ultimately, however, the 
increase of temperature must cause it to diminish. Then, when the tension 
is great enough, the molecular arrangements tend to be the strongest under 
the conditions, and increase of temperature can only weaken them, and 
therefore diminish the modulus. 
However, before this matter can be satisfactorily decided, it will be 
necessary to find out how the modulus changes as the load is gradually in- 
creased, and I hope shortly to have the honour of laying before the Society 
the results of experiments dealing with this part of the investigation. 
(. Issued separately October 23 , 1908 .) 
