Now, the mean or average interval between the centres of the two planets is 59.9643 of the earth's equatorial radii, or only about 237,000 miles. I say the mean or average interval. But it must be borne in mind that the form of the moon's orbit being an ellipse of eccentricity amounting to no less than 0.05484 of the major semi-axis of the ellipse itself, and the earth's centre being situated in its focus, if I could, in any manner, contrive to meet the moon, as it were, in its perigee, the above mentioned distance would be materially diminished.
