62 Presidential Address 



realities; so I urge, on the basis of the 

 electrical theory of matter. The Fitz- 

 gerald -Lorentz hypothesis I have an af- 

 fection for; I was present at its birth. 

 Indeed I assisted at its birth ; for it was in 

 my study at 21 Waverley Road, Liver- 

 pool, with Fitzgerald in an arm-chair, and 

 while I was enlarging on the difficulty 

 of reconciling the then new Michelson 

 experiment with the theory of astronomi- 

 cal aberration and with other known 

 facts, that he made his brilliant surmise: 

 "Perhaps the stone slab was affected by 

 the motion." I rejoined that it was a 45 

 shear that was needed. To which he 

 replied, " Well that's all right, a simple 

 distortion. " And very soon he said, 

 "And I believe it occurs, and that the 

 Michelson experiment demonstrates it." 

 A shortening long-ways, or a lengthening 

 cross-ways would do what was wanted. 

 (See Nature for 16 June, 1892.) 



And is such a hypothesis gratuitous? 

 Not at all: in the light of the electrical 

 theory of matter such an effect ought to 

 occur. The amount required by the 



