e Value of the Sun's Distance--Observations at
Dunsink of the Last Transit of Venus--The Question of an Atmosphere
to Venus--Other Determinations of the Sun's Distance--Statistics
about Venus.

It might, for one reason, have been not inappropriate to have commenced
our review of the planetary system by the description of the planet
Venus. This body is not especially remarkable for its size, for there
are other planets hundreds of times larger. The orbit of Venus is no
doubt larger than that of Mercury, but it is much smaller than that of
the outer planets. Venus has not even the splendid retinue of minor
attendants which gives such dignity and such interest to the mighty
planets of our system. Yet the fact still remains that Venus is peerless
among the planetary host. We speak not now of celestial bodies only seen
in the telescope; we refer to the ordinary observation which detected
Venus ages before telescopes were invented.

Who has not been delighted with the view of this glorious object? It is
not to be seen at all times. For months together the star of evening is
hidden from mortal gaze. Its beauties are even enhanced by the caprice
and the uncertainty which attend its appearance. We do not say that
there is any caprice in the movements of Venus, as known to those who
diligently consult their almanacs. The movements of the lovely planet
are there prescribed with a prosaic detail hardly in harmony with the
character usually ascribed to the Goddess of Love. But to those who do
not devote particular attention to the stars, the very unexpectedness of
its appearance is one of its greatest charms. Venus has not been
noticed, not been thought of, for many months. It is a beautifully clear
evening; the sun has just set. The lover of nature turns to admire the
sunset, as every lover of nature will. In the golden glory of the west a
beauteous gem is seen to glitter; it is the evening star--the planet
Venus. A few weeks later another beautiful sunset is seen, and now the
planet is no longer a point low down in the western glow; it has risen
high above the horizon, and continues a brilliant object long after the
shades of night have descended. Again, a little later, and Venus has
gained its full brilliancy and splendour. All the heavenly host--even
Sirius and even Jupiter--must pale before the splendid lustre of Venus,
the unrivalled queen of the firmament.

After weeks of splendour, the height of Venus at sun