( 567 ) 
rence will lead us to the same result that Mossorrr attained by 
means of the supposed inequality of the attractive and the repulsive 
forces. 
S 6. I shall suppose that each of the two disturbances of the 
aether is propagated with the velocity of light, and, taken by itself, 
obeys the ordinary laws of the electromagnetic field. These laws are 
expressed in the simplest form if, besides the dielectric displacement 
d, we consider the magnetic force 5, both together determining, 
as we shall now say, one state of the aether or one field. In accor- 
dance with this, I shall introduce two pairs of vectors, the one d, 5 
belonging to the field that is produced by the positive ions, whereas 
the other pair >, £' serve to indicate the state of the aether which 
is called into existence by the negative ions. I shall write down two 
sets of equations, one for >, ), the other for ’, ', and having the 
form which I have used in former papers!) for the equations of the 
electromagnetic field, and which is founded on the assumption that 
the ions are perfectly permeable to the aether and that they can be 
displaced without dragging the aether along with them. 
I shall immediately take this general case of moving particles. 
Let us further suppose the charges to be distributed with finite 
volume-density, and let the units in which these are expressed be 
chosen in such a way that, in a body which exerts no electrical 
actions, the total amount of the positive charges has the same nume- 
rical value as that of the negative charges. 
Let g be the density of the positive, and g' that of the negative 
charges, the first number being positive and the second negative. 
Let » (or »') be the velocity of an ion. 
Then the equations for the state (d, ) are *) 
Dw Y= 6 \ 
Dw Hi 0 
; (I) 
Rot H=4a09+4md 
22 ae at! 
47 V" Rot} = — S$; 
1) Lorentz. La théorie électromagnétique de MaxweLr et son application aux 
corps mouvants, Arch. Néerl. XXV, p. 363; Versuch einer Theorie der electrischen 
und optischen Erscheinungen in bewegten Korpern. 
ddx , dd dd 
Shh ies Wm ee ne 
) Div d 3e dy — 5: 
Rot d is a vector, whose components are —— zn nen 4 OE 
z 
