366 E. F. J. Love: Michelson-Morley Experiment. 



inertia. It was possibly owing to this reluctance that the experi- 

 ments of Morley and Miller ^ which proved the null result of the 

 Michelson-Morley experiment to be independent of the material of. 

 which the apparatus was constructed, were regarded more as a 

 cause for wonder than as — what they really were — a brilliant con- 

 formation of Larmor's predictions 



Times have changed. Owing to researches such as those in. 

 which Thonason, the Curie's and Rutherford were pioneers — 

 researches far removed from the domain of experimental optics — 

 the electron theory of atomic constitution may be regarded as 

 firmly established, quite as much so as the atomic theory itself. 

 Ihis being the case, we are entitled to assume it as the basis of. 

 argument, instead of its conclusion. Under these conditions, the 

 occurrence of the Fitzgerald-Lorentz contraction is no longer a. 

 hypothesis, but an immediate deduction from our theory of matter.. 

 The Michelson-Morley experiment, combined w'ith this deduction,, 

 then takes its rightful place among the evidences for the relative- 

 independence of material and etherial motion — a place of pre- 

 eminence, as it is the only experiment on the subject yet designed,, 

 much less completed, in which quantities of the second order of 

 smallness are involved in measurable fashion. This, then, we take- 

 to be its real significance; it is a valuable piece of evidence, 

 perhaps the most valuable we have, in favour of the very theory 

 which it was at first supposed to have disproved. 



If this idea be correct, it is important to notice that it holds 

 good independently of all questions as to the relation between the 

 Lorentzian electrodynamics and modern relativity doctrines. 

 "Whether the Principle of Relativity be the expression of a profound 

 physical truth or a brilliant mathematical speculation, the signifi- 

 cance of Michelson and Morley's result, as a demonstration of the 

 independence of the motion of the earth and ether, remains the- 

 same. 



1 Phil. Ma«f. [vi.], ix., 1905, p. 6S0. 



