( 8o? ) 
Why they do not alwayes move equal fpaces in equal times - 7 nor 
alwayes in a Line preci\ely (freight, ( there being almoft none 
fuch in Nature ) but fometimes with an Inclination of its Diske, 
fo as to make a Parabola, yet never the Segment of a Circle 1 : 
How they obferve two motions 3 an Excernal,.and Internal or Na- 
tural ? How one of the flat fides of the Cometick Diske refpe<ft- 
eth the Sun, as the Magnetick Needle does the North-Pole f 
Why the Motion of Comets is fwifteft, where the Sun-beams 
fall perpendicularly on it ? Why the motion of a recent Come- 
tick matter is made spirally £ Why that Spiral is not the fame 
iii all Comets? Why one Comet moves much fwifter than 
another £ Why the motion of one and the fame Comet increa- 
feth and decreafeth .? How a new Comet ifiTues out of its A tmo- 
fphere tf That the denfeft Comets move fwifteft. That, though 
the motion of Comets be unequal, yet 'tis not irregular. Whe- 
therComets alwayes are moft vigorous in the middle of their way? 
When Comets defcribe a Semi-paraboU only ? Why Comets 
are almoft never peraeiv'd by Us ; when they firft emerge out of 
their Atmofphere? That the motion of Comets hath a con- 
formity with that of Ships. That the Sun does the fame in the 
deviation of Comets, what a Pilot or Ship-mafter doth by the 
meanes of Cables in the direction of Sayling. That Comets, 
like Ships,defcribe fometimes an entire,fometimes a Semi-para- 
boU That it appears by the inflexion of the Traje<5bry line, whe- 
ther the way of the Comet be Circular or Ellipick or Paraboli* 
cat. Why this motion is rather Parabolical, than Hyperbolical? 
That the greateft deviation of Comets from the line of -directi- 
on is fcarce of two degrees > though 'tis not altogether improba- 
ble, but that in fome it may be a little greater, efpecially in thofe ? . 
that traverfe through a much vafter fpaceof the Heavens^ than 
others, and are of a very long duration: That the matter and 
figure of a Comet 5 and the impetus at firft imprefled 5 make 
much to its motion : That Comets, which come out of larger 
Atmofpheres, and from about their iEqnator, and are of a corn- 
pad body, are fwifteft, and efpecially thofe, that have their rife 
from the Sun. How the motion of the Spots of the Sun may be 
compared with that of Comets ? How the greateft velocity and 
tardity of the motion of Comets may be limited f That there 
k z Lihratory motion in Comets as well as inthe Moon, &c. 
The 
