11. Their Motion according to the Succession of the Signs, or contrary; and of the Motion of the Pri∣mum Mobile.
SOme Comets have moved according to the Suc∣cession of the Signs, as those of the Years 1592. and 1607. Some contrary, as they of the Years 1556. and 1618. with many others. Some that were at first Retrograde, have become direct; as that in 1556. and some that were at first Direct, have become Re∣trograde, or Stationary; as were those of the Years 1569. and 1582.
That they have a Diurnal Motion (or a Motion agreeing to that of the Primum Mobile) is evident be∣cause that the most part of such as appeared in the Morn∣ing, have return'd in the dawning of the day, or be∣fore; but were not to be se••n at Sun-set, or Twilight, in the same place where they were in the Morning, as they should have been if they had remained in the same place, or had moved only by their own Motion. In like manner, the great••st part of those that are seen in the Evening, do so appear, after Sun-s••t, above the West part of the Horizon, that (notwithstand∣ing their Motion according to the Succession of Signs) some set in the West before Midnight; others, at least before the Sun rise next Morning; yet among these some rise in the Evening, and set in the Morn∣ing, (as the Comet, 119.) Some are visible all the Night long, or set not at all, (as did those included within the Circle of ••hose Stars that never s••t; viz. the Comets of the Years 1513. 1533. and 1556.