It is attached to the earth so that it catches the magnetic force flowing out from the earth and then returns it to the earth as needed, for which reason it's course around the earth is also just as extensive; for this always depends on the greater or lesser quantity of the magnetic presence on the earth; and on the contrary, however, also the course of the moon, as a carrier of this substance, depends on the possible need of the earth for this natural life-substance. This is the main function of the moon. – The Moon, Chapter 1, Paragraph 2