osity woven round the entire trio.[1345] One of
them faded from view September 5; the other actually outshone the
original comet on August 31, but was plainly of inferior vitality. It
was last seen by Barnard on November 25, with the thirty-six inch
refractor, while its primary afforded an observation for position with
the twelve-inch, March 20, 1890.[1346] A cause for the disruption it had
presumably undergone had, before then, been plausibly assigned.

The adventures of Lexell's comet have long served to exemplify the
effects of Jupiter's despotic sway over such bodies. Although bright
enough in 1770 to be seen with the naked eye, and ascertained to be
circulating in five and a half years, it had never previously been seen,
and failed subsequently to present itself. The explanation of this
anomaly, suggested by Lexell, and fully confirmed by the analytical
inquiries both of Laplace and Leverrier,[1347] was that a very close
approach to Jupiter in 1767 had completely changed the character of its
orbit, and brought it within the range of terrestrial observation; while
in 1779, after having only twice traversed its new path (at its second
return it was so circumstanced as to be invisible from the earth), it
was, by a fresh encounter, diverted into one entirely different. Yet the
possibility was not lost sight of that the great planet, by inverting
its mode of action, might undo its own work, and fling the comet once
more into the inner part of the solar system. This possibility seemed to
be realized by Chandler's identification of Brooks's and Lexell's
comet.[1348] An exceedingly close approach to Jupiter in 1886 had, he
found reason to believe, produced such extensive alterations in the
elements of its motion as to bring the errant body back to our
neighbourhood in 1889. But his inference, though ratified by Mr. Charles
Lane Poor's preliminary calculations, proved dubious on closer inquiry,
and was rendered wholly inadmissible by the circumstances attending the
return of Brooks's comet in 1896.[1349] The companion-objects watched by
Barnard in 1889 had by that time, perhaps, become dissipated in space,
for they were not redetected. They represented, in all likelihood,
wreckage from a collision with Jupiter, dating, perhaps, so far back as
1791, when Mr. Lane Poor found that one of the fateful meetings to which
short-period comets are especially subject had taken place.

The Lexell-Brooks case was almost duplicated by th