rof. William C. Pickering, basing his statement on the result of
observations at the mountain observatory of Arequipa, says: "We may feel
reasonably certain that at the planet's [Venus's] surface the density of
its atmosphere is many times that of our own."

We do not have to depend upon the spectroscope for evidence that Venus
has a dense atmosphere, for we can, in a manner, _see_ her atmosphere,
in consequence of its refractive action upon the sunlight that strikes
into it near the edge of the planet's globe. This illumination of
Venus's atmosphere is witnessed both when she is nearly between the sun
and the earth, and when, being exactly between them, she appears in
silhouette against the solar disk. During a transit of this kind, in
1882, many observers, and the present writer was one, saw a bright
atmospheric bow edging a part of the circumference of Venus when the
planet was moving upon the face of the sun--a most beautiful and
impressive spectacle.

Even more curious is an observation made in 1866 by Prof. C.S. Lyman, of
Yale College, who, when Venus was very near the sun, saw her atmosphere
_in the form of a luminous ring_. A little fuller explanation of this
appearance may be of interest.

When approaching inferior conjunction--i.e., passing between the earth
and sun--Venus appears, with a telescope, in the shape of a very thin
crescent. Professor Lyman watched this crescent, becoming narrower day
after day as it approached the sun, and noticed that its extremities
gradually extended themselves beyond the limits of a semicircle, bending
to meet one another on the opposite side of the invisible disk of the
planet, until, at length, they did meet, and he beheld a complete ring
of silvery light, all that remained visible of the planet Venus! The
ring was, of course, the illuminated atmosphere of the planet refracting
the sunlight on all sides around the opaque globe.

In 1874 M. Flammarion witnessed the same phenomenon in similar
circumstances. One may well envy those who have had the good fortune to
behold this spectacle--to actually see, as it were, the air that the
inhabitants of another world are breathing and making resonant with all
the multitudinous sounds and voices that accompany intelligent life. But
perhaps some readers will prefer to think that even though an atmosphere
is there, there is no one to breathe it.

[Illustration: VENUS'S ATMOSPHERE SEEN AS A RING OF LIGHT.]

As the visibility of Venu