1919.] The Sixth Indian Science Congress. cix 
It should be noted here that there is an exact concordance 
, of 
There is one suggestion supplied by this concordance, however, 
which may be of far-reaching importance. In order that Mac- 
the medium. This may accordingly be taken to be implied 
in the electromagnetic theory on Maxwell’s scheme, so that 
the medium postulated therein, cannot be that of a stagnant 
ether. 
A further point emerges from this concordance that is 
also worthy of note. It is assumed in Maxwell’s theory that 
the electrostatic energy is potential and electromagnetic 
energy is kinetic. On the above concordance, therefore, the 
potential energy is due to molecular rotation. And if, further, 
we agree that this molecular rotation corresponds to a vertical 
spin, we must be disposed to agree that the so-called potential 
energy is also in reality kinetic. 
Thus, when a body is charged, a subtle ethereal motion 
must be conceived to be induced in the field, surrounding it, 
(and inside it), and the corresponding kinetic energy would 
then account, partly or wholly, for the static energy—so-called 
—of the electrostatic field. 
Again, when radiation is propagated through the (ethereal) 
medium, the propagation is associated with convected momen- 
tum of the field, which accounts for the entire energy of this 
radiation. It is this momentum which seems to appear in Poyn- 
energy. 
This would indicate that the entire energy concerned in 
the propagation of radiation is entirely kinetic and, in this event, 
the intrinsic energy postulated above must also be entirely 
kinetic. If this be so, the ethereal medium in free space may 
prove to be neither stagnant nor immobile. 
may have relation to the propagation of gravitation, in the 
nature, conceivably, of longitudinal waves, propagated with 
very high velocities. 
At the time Tait wrote his recent advances, the doctrine 
of energy had been placed on what then appeared to be a firm 
