202 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 10 
sion are readily comprehended if K has these dimensions. In other 
words, K is inversely as current X a frequency; or inversely as electric 
quantity x angular acceleration; or it is inversely as the square of a 
velocity, the velocity being the velocity of long etherial waves in the 
medium. 
All of these have a meaning. For example K being inversely as 
electric quantity x angular acceleration would mean that K was directly 
proportional to the square of the number of electrons per cc. = a 
and 1 + angular acceleration might be the “‘laxity’’ of the electrons. 
2 
Also as 7 is elasticity, K is inversely as an elasticity. 
While the numerical value of » is very nearly unity, except in 
paramagnetic and ferromagnetic substances, K varies from unity to 
80 in dielectrics and to infinity in perfect conductors in which electro- 
magnetic waves will be stopped. 
The other great etherial constant is that of gravitational permeability, 
G. The numerical value of this constant for all known substances is 
so near unity that the constant itself is usually omitted from the 
formulas of gravitational attraction. And accordingly it is usually 
assumed that the gravitational attraction of two masses does not 
depend on the medium. ‘This, however, must be an incorrect assump- 
tion if electromagnetic mass is also gravitational, as is probable. 
Electromagnetic or electrostatic attractions involve the medium, and 
as matter is nothing but electrical charges its mutual attraction must 
so depend also. 
The Newtonian law of attraction shows this necessity also. 
The following reasoning equally indicates this. 
While electric quantity, or (e), is independent of the medium, the 
force between charges, i.e., the attraction or repulsion of two charges, 
depends upon the medium. It depends on the specific inductive 
capacity, or K. Similarly while quantity of magnetism, or magnetic 
flux, that is electricity in motion, does not depend on the medium, the 
force between two poles or two currents does so depend. It involves 
u, the magnetic permeability. Just so in the case of mass. While the 
quantity of mass is independent of the medium, the force between two 
masses, which is called gravitation, or weight, must depend on the 
medium. ‘This is a necessary consequence of the electrical constitu- 
tion of matter. Gravitation must involve a quality of the medium 
which we may call the gravitational permeability and designate by G. 
