inking--sinking into the obscurity from whence it emerged so briefly,
and its place in the sky knows it no more. It may be there still, but
so infinitely faint and far away that no power at our command can reveal
it to us. And the amazing part of it is that this huge disaster, this
mighty conflagration, is not actually happening as it is seen, but has
happened many hundreds of years ago, though the message brought by the
light carrier has but reached us now.

There have not been a great many such outbursts recorded, though many
may have taken place unrecorded, for even in these days, when trained
observers are ceaselessly watching the sky, 'new' stars are not always
noticed at once. In 1892 a new star appeared, and shone for two months
before anyone noticed it. This particular one never rose to any very
brilliant size. I twas situated in the constellation of Auriga, and was
noticed on February 1. It remained fairly bright until March 6, when it
began to die down; but it has now sunk so low that it can only be seen
in the very largest telescopes.

Photography has been most useful in recording these stars, for when one
is noticed it has sometimes been found that it has been recorded on a
photographic plate taken some time previously, and this shows us how
long it has been visible. More and more photography becomes the useful
handmaid of astronomers, for the photographic prepared plate is more
sensitive to rays of light than the human eye, and, what is more useful
still, such plates retain the rays that fall upon them, and fix the
impression. Also on a plate these rays are cumulative--that is to say,
if a very faint star shines continuously on a plate, the longer the
plate is exposed, within certain limits, the clearer will the image of
that star become, for the light rays fall one on the top of the other,
and tend to enforce each other, and so emphasize the impression, whereas
with our eyes it is not the same thing at all, for if we do not see an
object clearly because it is too faint, we do not see it any better,
however much we may stare at the place where it ought to be. This is
because each light ray that reaches our eye makes its own impression,
and passes on; they do not become heaped on each other, as they do on a
photographic plate.

One variable star in Perseus, discovered in 1901, rose to such
brilliancy that for one night it was queen of the Northern Hemisphere,
outshining all the other first-class stars.