n it
disappeared. The exact day is unknown, as during that interval the
constellation of the Serpent-Bearer is above the horizon in the day-time
only. But in February 1606, when it again became possible to look for
the new star in the night-time, it had vanished. It probably continued
to glow with sufficient lustre to have remained visible, but for the
veil of light under which the sun concealed it, for about sixteen months
altogether. In fact, it seems very closely to have resembled Tycho's
star, not only in appearance and in the degree of its greatest
brightness, but in the duration of its visibility.

In the year 1670 a new star appeared in the constellation Cygnus,
attaining the third magnitude. It remained visible, but not with this
lustre, for nearly two years. After it had faded almost out of view, it
flickered up again for awhile, but soon after it died out, so as to be
entirely invisible. Whether a powerful telescope would still have shown
it is uncertain, but it seems extremely probable. It may be, indeed,
that this new star in the Swan is the same which has made its appearance
within the last few weeks; but on this point the evidence is uncertain.

On April 20, 1848, Mr. Hind (Superintendent of the Nautical Almanac,
and discoverer of ten new members of the solar system) noticed a new
star of the fifth magnitude in the Serpent-Bearer, but in quite another
part of that large constellation than had been occupied by Kepler's
star. A few weeks later, it rose to the fourth magnitude. But afterwards
its light diminished until it became invisible to ordinary eyesight. It
did not vanish utterly, however. It is still visible with telescopic
power, shining as a star of the eleventh magnitude, that is five
magnitudes below the faintest star discernible with the unaided eye.

This is the first new star which has been kept in view since its
apparent creation. But we are now approaching the time when it was found
that as so-called new stars continue in existence long after they have
disappeared from view, so also they are not in reality new, but were in
existence long before they became visible to the naked eye.

On May 12, 1866, shortly before midnight, Mr. Birmingham, of Tuam,
noticed a star of the second magnitude in the Northern Crown, where
hitherto no star visible to the naked eye had been known. Dr. Schmidt,
of Athens, who had been observing that region of the heavens the same
night, was certain that up to 11 P.M.