The earth's rotation on its axis remains unaltered during this increasing orbital velocity, consequently the aetherial currents generated by the earth will remain uniform, and the moon will still be circled round the earth in the same period of about 28 days. But while the time of the moon's revolution remains unaltered, the orbit that she has to describe is now increased owing to the increased orbital velocity of its central body, with the result, that by the time the earth gets to that part of its orbit represented by point _D_, it is then two millions of miles nearer to the sun than at point _C_, and will be circled round the sun by the aetherial currents at a much greater rate. Therefore, the eccentricity of the moon's orbit is increased just in proportion to the increased velocity of the earth in its orbit round the sun. By the time the earth has arrived at point _A_, when it is only a distance of about 91 millions of miles from the sun, it reaches the minimum distance, and is circled round at the decreased distance with its maximum velocity. At this point, therefore, the eccentricity of the orbit of the moon will be at its greatest, and, if one revolution could be represented by an ellipse _E_ _G_ _H_, then that ellipse would be more elongated, and the difference between the two axes of the moon's orbit would be greater than at any other point of the earth's orbit. Thus it can readily be seen that the eccentricity of the moon's orbit is primarily due to the different velocities of the central body, in this case the earth, as that body is carried round its central body, the sun. Where the earth's motion is slowest, there the eccentricity of the moon's orbit will be at a minimum; but where the earth's velocity is greatest, there the eccentricity of the moon's orbit will be at a maximum. Between this minimum and maximum velocity of the earth in its orbit there is the constant increase or decrease in the eccentricity of the orbit of the moon; the eccentricity increasing as the orbital velocity of the central body increases, and decreasing as the orbital velocity of the earth decreases. A further fact has, however, to be taken into consideration, which is that the primary body about which the moon revolves is itself subject to the same eccentricity of its orbit, and for similar reasons, as we shall see later on. So that when the eccentricity of the earth's orbit is at its greatest, then the moon's orbit will possess its greatest possible eccentricity, and as the eccentricity of the earth's orbit is dependent upon the orbital velocity of the sun, so the greatest possible eccentricity of the moon's orbit is indirectly connected and associated with the sun's motion through space, which motion will now be considered.