er, and
more widely-dispersed streaks. And it cannot be doubted that the minute
fragments which no telescopic aid makes visible, are yet more numerous
and widely dispersed. Thus far, then, inference and observation are at
one.

Granting that the great majority of these outlying portions of nebulous
matter will be drawn into the central mass long before it reaches a
definite form, the presumption is that some of the very small,
far-removed portions will not be so; but that before they arrive near
it, the central mass will have contracted into a comparatively moderate
bulk. What now will be the characters of these late-arriving portions?

In the first place, they will have either extremely eccentric orbits or
non-elliptic paths. Left behind at a time when they were moving towards
the centre of gravity in slightly-deflected lines, and therefore having
but very small angular velocities, they will approach the central mass
in greatly elongated curves; and rushing round it, will go off again
into space. That is, they will behave just as we see the majority of
comets do; the orbits of which are either so eccentric as to be
indistinguishable from parabolas, or else are not orbits at all, but are
paths which are distinctly either parabolic or hyperbolic.

In the second place, they will come from all parts of the heavens. Our
supposition implies that they were left behind at a time when the
nebulous mass was of irregular shape, and had not acquired a definite
rotation; and as the separation of them would not be from any one
surface of the nebulous mass more than another, the conclusion must be
that they will come to the central body from various directions in
space. This, too, is exactly what happens. Unlike planets, whose orbits
approximate to one plane, comets have orbits that show no relation to
one another; but cut the plane of the ecliptic at all angles, and have
axes inclined to it at all angles.

In the third place, these remotest flocculi of nebulous matter will, at
the outset, be deflected from their direct courses to the common centre
of gravity, not all on one side, but each on such side as its form, or
its original proper motion, determines. And being left behind before the
rotation of the nebula is set up, they will severally retain their
different individual motions. Hence, following the concentrated mass,
they will eventually go round it on all sides; and as often from right
to left as from left to right. Here