104 Dr. 0. V. Burton on a 



the total force exerted per unit mass of matter being FpA; 

 while the remaining equal and opposite forces, acting 

 respectively on positive and negative electrons whose aggre- 

 gate charges are e^;, — e%, have the same effect on the motion 

 of those electrons as would be produced by an electromotive 

 intensity 



T = (F 1 ~F) W A _ (F-F 8 ) W A ( 



measured in the direction of the acceleration A. 



59. As in Appendix A, let it be assumed (merely by way 

 of example) that %=1, e being as before the quantity of 

 electricity required to liberate one gram of hydrogen electro- 

 lytically. Assume also that the extrusion of aether F per 

 unit mass of neutral matter is due entirely to negative 

 electrons ; the gether extruded by one gram of matter being* 

 therefore that extruded by a mass jjl 2 of negative electrons, 

 whose total charge is — e^ (= — e). Assume, that is to say,, 



F 1 = and Fj^i a = F^=FOtt 1 + A ij|) ; . . . (72) 



If we further assume (as in Appendix A, §57) that nearly 

 all the inertia of neutral ma Iter is the inertia of positive 

 electrons, so that /*i = l approximately, then (71) becomes 



T=-^, (73) 



which, with our present special assumptions, is the quasi- 

 electromotive intensity due to an acceleration A of the 

 aether. 



60. As regards the thermal effects arising from com- 

 pressional waves in the 93ther, let us simplify the problem to 

 be considered by reducing the disturbance (as in § 27) to a 

 single plane wave-train of very great wave-length \, and of 

 frequency n. Patting 5 in place of 2irn, we may write for 

 any region of dimensions very small compared with A, 



T = V* (71) 



where it is to be understood that T and T are expressed in 

 absolute electromagnetic measure. 



61. Consider in particular the case of a flat parallel-faced 

 slab of conducting material, whose length and breadth are 

 very great in comparison with its thickness, the main faces 

 of the slab being perpendicular to the direction in which the 

 compressional aetherial waves are being propagated, and 



