es since I commenced this discourse. It would make the
journey from the earth to the sun in five days. If it is now near the
centre of our universe it would probably reach its confines in a
million of years. So far as our knowledge goes, there is no force in
nature which would ever have set it in motion and no force which can
ever stop it. What, then, was the history of this star, and, if there
are planets circulating around, what the experience of beings who may
have lived on those planets during the ages which geologists and
naturalists assure us our earth has existed? Was there a period when
they saw at night only a black and starless heaven? Was there a time
when in that heaven a small faint patch of light began gradually to
appear? Did that patch of light grow larger and larger as million after
million of years elapsed? Did it at last fill the heavens and break up
into constellations as we now see them? As millions more of years
elapse will the constellations gather together in the opposite quarter
and gradually diminish to a patch of light as the star pursues its
irresistible course of two hundred miles per second through the
wilderness of space, leaving our universe farther and farther behind
it, until it is lost in the distance? If the conceptions of modern
science are to be considered as good for all time--a point on which I
confess to a large measure of scepticism--then these questions must be
answered in the affirmative.

The problems of which I have so far spoken are those of what may be
called the older astronomy. If I apply this title it is because that
branch of the science to which the spectroscope has given birth is
often called the new astronomy. It is commonly to be expected that a
new and vigorous form of scientific research will supersede that which
is hoary with antiquity. But I am not willing to admit that such is the
case with the old astronomy, if old we may call it. It is more pregnant
with future discoveries today than it ever has been, and it is more
disposed to welcome the spectroscope as a useful handmaid, which may
help it on to new fields, than it is to give way to it. How useful it
may thus become has been recently shown by a Dutch astronomer, who
finds that the stars having one type of spectrum belong mostly to the
Milky Way, and are farther from us than the others.

In the field of the newer astronomy perhaps the most interesting work
is that associated with comets. It must be confess