Page:On the Magnet - Gilbert (1900 translation of 1600 work).djvu/263



is part of the Arctick circle of the Zodiack, in which one period of obliquity is performed; from A to E is the period of the anomaly of the præcession of the æquinoxes; A I is the shape of the curved line which the pole of the Earth describes by a true motion compounded of the three motions, that is to say, of the æquable motion præcessional, of that of the anomaly of the præcessions, and that of obliquity.