same phenomenon. This was a narrow
straight ray, forming a tangent to the strong curve of the primary tail,
and reaching to a still greater distance from the nucleus. It continued
faintly visible for about three weeks, during part of which time it was
seen in duplicate. For from the chief train itself, at a point where its
curvature abruptly changed, issued, as if through the rejection of some
of its materials, a second beam nearly parallel to the first, the rigid
line of which contrasted singularly with the softly diffused and waving
aspect of the plume of light from which it sprang. Olbers's theory of
unequal repulsive forces was never more beautifully illustrated. The
triple tail seemed a visible solar analysis of cometary matter.

The processes of luminous emanation going on in this body forcibly
recalled the observations made on the comets of 1744 and 1835. From the
middle of September, the nucleus, estimated by Bond to be under five
hundred miles in diameter, was the centre of action of the most
energetic kind. Seven distinct "envelopes" were detached in succession
from the nebulosity surrounding the head, and after rising towards the
sun during periods of from four to seven days, finally cast their
material backward to form the right and left branches of the great
train. The separation of these by an obscure axis--apparently as black,
quite close up to the nucleus, as the sky--indicated for the tail a
hollow, cone-like structure;[1190] while the repetition of certain spots
and rays in the same corresponding situation on one envelope after
another served to show that the nucleus--to some local peculiarity of
which they were doubtless due--had no proper rotation, but merely
shifted sufficiently on an axis to preserve the same aspect towards the
sun as it moved round it.[1191] This observation of Bond's was strongly
confirmatory of Bessel's hypothesis of opposite polarities in such
bodies' opposite sides.

The protrusion towards the sun, on September 25, of a brilliant luminous
fan-shaped sector completed the resemblance to Halley's comet. The
appearance of the head was now somewhat that of a "bat's-wing" gaslight.
There were, however, no oscillations to and fro, such as Bessel had seen
and speculated upon in 1835. As the size of the nucleus contracted with
approach to perihelion, its intensity augmented. On October 2, it
outshone Arcturus, and for a week or ten days was a conspicuous object
half an hour after sun