comet having, in
that brief space, condensed, with a vivid outburst of light, into a
seeming star, and the seeming star having expanded back again into a
comet. Scarcely less transient, though not altogether similar, changes
of aspect were noted by M. Perrotin,[1342] January 13 and 19, 1884. On
the latter date, the continuous spectrum given by a reddish-yellow disc
surrounding the true nucleus seemed intensified by bright knots
corresponding to the rays of sodium.

A comet discovered by Mr. Sawerthal at the Royal Observatory, Cape of
Good Hope, February 19, 1888, distinguished itself by blazing up, on May
19, to four or five times its normal brilliancy, at the same time
throwing out from the head two lustrous lateral branches.[1343] These
had, on June 1, spread backward so as to join the tail, with an effect
like the playing of a fountain; ten or eleven days later, they had
completely disappeared, leaving the comet in its former shape and
insignificance. Its abrupt display of vitality occurred two full months
after perihelion.

On the morning of July 7, 1889, Mr. W. R. Brooks, of Geneva, New York,
eminent as a successful comet-hunter, secured one of his customary
trophies. The faint object in question was moving through the
constellation Cetus, and turned out to be a member of Jupiter's numerous
family of comets, revolving round the sun in a period of seven years.
Its past history came then, to a certain extent, within the scope of
investigation, and proved to have been singularly eventful; nor had the
body escaped scatheless from the vicissitudes to which it had been
exposed. Observing from Mount Hamilton, August 2 and 5, Professor
Barnard noticed this comet (1889, v.) to be attended in its progress
through space by four _outriders_, "The two brighter companions" (the
fainter pair survived a very short time) "were perfect miniatures,"
Professor Barnard tells us,[1344] "of the larger comet, each having a
small, fairly defined head and nucleus, with a faint, hazy tail, the
more distant one being the larger and less developed. The three comets
were in a straight line, nearly east and west, their tails lying along
this line. There was no connecting nebulosity between these objects, the
tails of the two smaller not reaching each other, or the large comet. To
all appearance they were absolutely independent comets." Nevertheless,
Spitaler, at Vienna, in the early days of August, perceived, as it were,
a thin cocoon of nebul