ens.
So far as we can determine, every stone that lies loose on its surface
has lain there through untold ages, unchanged and unmoved.

We cannot speak so confidently of the planets. The most powerful
telescopes yet made, the most powerful we can ever hope to make, would
scarcely shows us mountains, or lakes, rivers, or fields at a distance
of fifty millions of miles. Much less would they show us any works of
man. Pointed at the two nearest planets, Venus and Mars, they whet our
curiosity more than they gratify it. Especially is this the case with
Venus. Ever since the telescope was invented observers have tried to
find the time of rotation of this planet on its axis. Some have reached
one conclusion, some another, while the wisest have only doubted. The
great Herschel claimed that the planet was so enveloped in vapor or
clouds that no permanent features could be seen on its surface. The
best equipped recent observers think they see faint, shadowy patches,
which remain the same from day to day, and which show that the planet
always presents the same face to the sun, as the moon does to the
earth. Others do not accept this conclusion as proved, believing that
these patches may be nothing more than variations of light, shade, and
color caused by the reflection of the sun's light at various angles
from different parts of the planet.

There is also some mystery about the atmosphere of this planet. When
Venus passes nearly between us and the sun, her dark hemisphere is
turned towards us, her bright one being always towards the sun. But she
is not exactly on a line with the sun except on the very rare occasions
of a transit across the sun's disk. Hence, on ordinary occasions, when
she seems very near on a line with the sun, we see a very small part of
the illuminated hemisphere, which now presents the form of a very thin
crescent like the new moon. And this crescent is supposed to be a
little broader than it would be if only half the planet were
illuminated, and to encircle rather more than half the planet. Now,
this is just the effect that would be produced by an atmosphere
refracting the sun's light around the edge of the illuminated
hemisphere.

The difficulty of observations of this kind is such that the conclusion
may be open to doubt. What is seen during transits of Venus over the
sun's disk leads to more certain, but yet very puzzling, conclusions.
The writer will describe what he saw at the Cape of Good Hope during