ten thousand; six hundred and fifty of them being known to be binary,
or revolving on orbits--Prof. S. W. Burnham, the distinguished young
astronomer of the Dearborn Observatory, Chicago, having discovered eight
hundred within the last eight years. This discovery implies stupendous
motion; every fixed star is a sun like our own, and we can imagine these
wheeling orbs to be surrounded by cool planets, the abode of life, as
well as ours. If the orbit of a binary system lies edgewise toward us,
then one star will hide the other each revolution, moving across it and
appearing on the other side. Several instances of this motion are
known; the distant suns having made more than a complete circuit since
discovery, the shortest periodic time known being twenty-five years.

Wonderful as was this achievement of the micrometer, one not less
surprising awaited its delicate measurement. If one walks in a long
street lighted with gas, the lights ahead will appear to separate, and
those in the rear approach. The little spider lines have detected just
such a movement in the heavens. The stars in Hercules are all the time
growing wider apart, while those in Argus, in exactly the opposite part
of the Universe, are steadily drawing nearer together. This demonstrates
that our sun with his stately retinue of planets, satellites, comets,
and meteorites, all move in grand march toward the constellation
Hercules. The entire universe is in motion. But these revelations of the
micrometer are tame compared with its final achievement, the discovery
of parallax.

This means difference of direction, and the parallax of a star is the
difference of its direction when viewed at intervals of six months.
Astronomers observe a star to-day with a powerful telescope and
micrometer; and in six months again measure the same star. But meanwhile
the earth has moved 183,000,000 miles to the east, so that if the star