hat in each particular case. This fact is
therefore a very strong argument in favor of our theory.

Amidst the many anomalous peculiarities of comets, it has been noticed
that a short tail is sometimes seen at right angles to the principal
tail, and in a few cases pointing directly towards the sun. Much of this
may be owing to perspective, but granting the reality of the fact, it is
still explicable on the same general principles.

In speaking of the modifying causes which influence the weather, we
mentioned the effect due to the position of the sun with respect to the
axis of the vortex. This will be found to have a sensible effect on the
action of the radial stream. The natural direction of a comet's electric
stream is _towards_ the axis of the vortex, and in the central plane of
the vortex it will be also towards the sun. But this stream is met by
the stronger radial stream from the axis, and as Mr. Hind describes it,
"is driven _backward_ in two streams passing on either side of the head,
and ultimately blending into one to form the tail." Now, if the body of
the sun be situated between the comet and the axis of the vortex, it
will shield the comet from the action of the radial stream, and thus a
tail may really point towards the sun.

In 1744 a brilliant comet exhibited six distinct tails spread out like a
fan, some seven days after its perihelion passage; its distance from
the sun at the time not being more than a third of the earth's distance.
The comet was then rapidly approaching the plane of the ecliptic, and if
we make the calculation for the position of the sun, we shall find that
the body of the sun was on the same side of the axis of the vortex as
the comet, and that the comet was then situated at the boundaries of the
conical space, enclosed by the radial stream in its deflected passage
round the body of the sun. In this position there are numerous cross
currents of the stream, and hence the phenomenon in question. As this
fact rests on the testimony of one individual, and is an occurrence
never recorded before or since, many are disposed to doubt the fact, yet
our theory explains even this peculiarity, and shows that there is no
necessity for impugning the statement of Cheseaux.

Another unexplained phenomenon is the corruscation of the tail. It has
been attempted to explode this fact also, by referring it to conditions
of our own atmosphere; and it is generally considered the argument of
Olbers, foun