116 PHYSICS OF ETHER 



( 

 and the other perpendicular, into a plane at right angles to the mer- 



idian where both components would be at right angles to the drift, 

 and therefore where no differential effect would be produced, no 

 change in the field of view could be detected. Had there been a 

 total difference of 7.8 X 10~ 13 of the whole velocity between the com- 

 ponents, the effect would have been manifest. We may, therefore, 

 conclude that there is no third order effect. How well the various 

 theories of a quiescent ether will lend themselves to this further 

 adaptation remains to be seen, but undoubtedly by properly choosing 

 the coefficients it may be done; however, any theory which does not 

 contain explicitly the exact and complete adaptation to all orders of 

 the aberration must certainly impress itself as highly artificial in its 

 successive auxiliary hypotheses and approximations. 



Larmor, in reference to his theory, says, " It is, in fact, found that 

 the Maxwellian circuital equations of SBthereal activity, in the am- 

 bient aether referred to axes moving along with the uniform velocity 

 of convection, v, can be reduced to the same form as for axes at rest 



up to and including ( J but not I - 1 by adopting certain coeffi- 



cients." "If, then, matter is for physical purposes a purely aethereal 

 system, if it is constituted of simple polar singularities or electrons, 

 positive and negative, in the Maxwellian aether, the nuclei of which 

 may be either practically points or else small regions of aether with 

 internal connections of pure constraint, the propositions above stated 



v 

 for the first order are extended to the second order of with the 



single addition of the Fitzgerald-Lorentz shrinkage in the scale of 

 space and an equal one in the scale of time, which, being isotropic, 

 is unrecognizable." "On such a theory as this the criticism presents 

 itself, and was in fact at once made, that one hypothesis is needed 

 to annul optical effects to the first order; that when these were 

 found to be actually null to the second order, another hypothesis 

 had to be added : and that another hypothesis would be required for 

 the third order, while in fact there was no reason to believe that they 

 were not exactly null to all orders. Such a train of remarks indicates 

 that the nature of the hypothesis has been overlooked. And if indeed 

 it could be proved that the optical effect is null up to the third order, 

 that circumstance would not demolish the theory, but would rather 

 point to some finer adjustment than it provides for; needless to say 

 the attempt would indefinitely transcend existing experimental possi- 

 bilities." And further, "up to the first order the electron hypo- 

 thesis, that electricity is atomic, suffices by itself, as Lorentz was 

 first to show." "Up to the second order, the hypothesis that matter 

 is constituted electrically of electrons is required in addition." 

 The necessity in view of the present experimental data for leaving 



