Without going back of the nineteenth century we may find records of
some of the most extraordinary comets that man has ever looked upon.
In 1811, still spoken of as ``the year of the comet,'' because of the
wonderful vintage ascribed to the skyey visitor, a comet shaped like a
gigantic sword amazed the whole world, and, as it remained visible for
seventeen months, was regarded by superstitious persons as a symbol of
the fearful happenings of Napoleon's Russian campaign. This comet, the
extraordinary size of whose head, greatly exceeding that of the sun
itself, has already been mentioned, was also remarkable for exhibiting
so great a brilliancy without approaching even to the earth's distance
from the sun. But there was once a comet (and only once -- in the year
1729) which never got nearer to the sun than four times the distance
of the earth and yet appeared as a formidable object in the sky. As
Professor Young has remarked, ``it must have been an enormous comet to
be visible from such a distance.'' And we are to remember that there
were no great telescopes in the year 1729. That comet affects the
imagination like a phantom of space peering into the solar system,
displaying its enormous train afar off (which, if it had approached as
near as other comets, would probably have become the celestial wonder
of all human memory), and then turning away and vanishing in the
depths of immensity.

In 1843 a comet appeared which was so brilliant that it could be seen
in broad day close beside the sun! This was the first authenticated
instance of that kind, but the occurrence was to be repeated, as we
shall see in a moment, less than forty years later.

The splendid comet of 1858, usually called Donati's, is remembered by
many persons yet living. It was, perhaps, both as seen by the naked