aque, have appeared a
few minutes later, projected on the sun's disk; but not a trace of it
could be seen. The sun was approaching Table Mountain at the critical
moment, and its limb was undulating badly, making the detection of a
minute point difficult. The possibility of a very small opaque nucleus
is therefore still left open; yet the remarkable conclusion still holds,
that, immediately around a possible central nucleus, the matter of the
head of the comet was so rare as not to intercept any appreciable
fraction of the sun's light. This result seems also to show that, with
the possible exception of a very small central mass, what seems to
telescopic vision as a nucleus is really only the central portion of the
coma, which, as the distance from the centre increases, becomes less and
less dense by imperceptible gradations.

Another fact tending towards this same conclusion is that after this
comet passed perihelion it showed several nuclei following each other.
Evidently the powerful attraction of the sun had separated the parts of
the apparent nucleus, which were following each other in nearly the same
orbit. As they could not have been completely brought together again, we
may suppose that in such cases the smaller nuclei were permanently
separated from the main body. In addition to this, the remarkable
similarity of the orbit of this comet to that of several others
indicates a group of bodies moving in nearly the same orbit. The other
members of the group were the great comets of 1843, 1880 and 1887. The
latter, though so bright as to be conspicuous to the naked eye, showed
no nucleus whatever. The closely related orbits of the four bodies are
also remarkable for approaching nearer the sun at perihelion than does
the orbit of any other known body. All of these comets pass through the
matter of the sun's corona with a velocity of more than 100 m. per
second without suffering any retardation. As it is beyond all reasonable
probability that several independent bodies should have moved in orbits
so nearly the same, the conclusion is that the comets were originally
portions of one mass, which gradually separated in the course of ages by
the powerful attraction of the sun as the collection successively passed
the perihelion. It may be remarked that observations on the comet of
1843 seemed to show a slight ellipticity of the orbit, corresponding to
a period of several centuries; but the deviation of all the orbits from
a p