This pressure only gives the result due to the pressure of one cubic foot of sunlight. What must be the pressure, therefore, due to the whole of the sunlight received by the flat body from the sun? The total pressure, whatever it may be, would be equal to 2 P. according to Maxwell, and half of that is due to electricity, and half due to magnetism. Now such a result is entirely in harmony with the conception of the Aether as given in this work. For, if Aether possess an electric basis as suggested by Maxwell, and it is also gravitative as suggested in Art. 45, then it must follow, as pointed out in a previous Art., that throughout the field there is a varying difference in the potential of the field; the potential being regulated by the electric density, that density being equivalent to the aetherial density. Further, as the elasticity of the medium which regulates the pressure is proportional to the density, so the pressure must decrease, as the elasticity decreases--that is, as the electric potential decreases, or the electric density is diminished. Therefore, if the sun be an electrified body, ever generating electro-magnetic waves which speed away from it on every side, then, whenever any of these waves come into contact with a planet or comet, that planet or comet would be repelled from the sun by the pressure of these electro-magnetic waves to which the sun gives rise in its electric or electro-magnetic field. Thus we again come to the conclusion that the sun is not only the centre of a centripetal force due to Gravitation, and subject to certain laws, whose physical cause is unknown, but it is equally the centre and source of a centrifugal force, in that it is an electrified body, and gives rise to electric waves which produce a pressure on any body upon which they fall, in the sun's electric or aetherial field. It has only to be demonstrated, therefore, that this centrifugal force satisfactorily fulfils all the laws required as laid down in Art. 24, that is, that its course is along the same path as the Centripetal Force of Gravitation, that it is subject to the same law of intensity, which is inversely as the square of the distance; and further (what is the most important at this stage), that the combined effect of the pressure of two bodies is equal to the product of their masses, then we shall have discovered that which we set out to discover, viz. a complementary force to the attractive force of Gravitation. Unlike the centripetal force, however, the centrifugal force will be purely a physical one, due to a purely physical medium, the Aether, whose properties and motions can be accounted for on a physical, and not on a hypothetical basis.