Chase.] 4:Ub [June 17, 



theory of currents, we are reminded of tlie orbital equations, and if we 

 still think of mass, it is only because we have learned to regard mass as a 

 necessary element of force. If we look still further, and see that the pro- 

 duct of two masses must be considered in order to secure strict accuracy 

 in the determination of orbits, we can find no good meaning for the square 

 root of a mass. But if electric phenomena are simply the result of oscilla- 

 tions in the luminiferous sether, which represent the actions and reactions 

 of inertia and elasticity, we may reasonably look for analogous phenomena 

 in cosmical arrangements. 



80. Cosmical Illustration. 



— \m 



In the mutual actions and reactions of two masses, « = \/gr oc V— oc 



m 



1/ m ■* v^ oc in; — ■ oc v. Let m^, m^, m-^ designate Sun, Earth, Jupiter ; 



%, Earth's aphelion velocity ; v^, velocity of light. Then we find 

 m.Q m.^ m^ in^ 

 «A ■ «3 ■■ % "■ «^ 



Yor,'o^ = ps -=- 497.837; 1)3 = 27:p3 -^ 1.01677 h- 31558149; m^ = 

 1047.879^5. Substituting these values, we find: m^ = 316.9 TO3 ; Wq = 

 332,072 TO3; p3^= 92,559,700 miles. Hence we see that the reaction of 

 Earth against the forces which produce its orbital velocity, at the moment 

 when it is least affected by Sun, is a mean proportional between the re- 

 actions of Sun and Jupiter against the velocity of light. In other words, 

 the reaction of inertia at the centre of density (Earth) against the inertia 

 at the centre of nebulosity (Jupiter) and at the centre of nucleation (Sun) 

 is limited in each direction by the reactions of controlling inertia against 

 sethereal elasticity. 



Multiplying the terms of the above proportion by v^ v^, we have 



The importance of the reactionary vis viva at the centre of condensation 

 is thus shown, and the vis viva at the coordinate centres represents a mean 

 proportional between the sethereal and the central orbital vis viva. 



81. Mutual Convertibility of Oravity and Magnetism. 



In the first set of electrostatic, magnetic and electrokinetic pairs, the 

 product of the two dimensions represents an energy, or vis viva. Max- 

 wellf gives the following equations : 



YUM-\ 



leE^ = [wi2] = ipC^ = [-^^ J- 



The symbols denote, respectively, the products of quantity of electricity 

 by electric potential, quantity of free magnetism by magnetic potential, 



* Because r represents the distance between the two masses and does not 

 affect the ratio. 

 t Elec. and Mag., ii, 240, 



