we examine the shape of the former's orbit. Venus's mean distance from
the sun is 67,200,000 miles, and her orbit is so nearly a circle, much
more nearly than that of any other planet, that in the course of a
revolution her distance from the sun varies less than a million miles.
The distance of the earth varies 3,000,000 miles, and that of Mercury
14,000,000. Her period of revolution, or the length of her year, is 225
of our days. When she comes between the sun and the earth she approaches
us nearer than any other planet ever gets, except the asteroid Eros, her
distance at such times being 26,000,000 miles, or about one hundred and
ten times the distance of the moon.

Being nearer to the sun in the ratio of 67 to 93, Venus receives almost
twice as much solar light and heat as we get, but less than one third as
much as Mercury gets. There is reason to believe that her axis, instead
of being considerably inclined, like that of the earth, is perpendicular
to the plane of her orbit. Thus Venus introduces to us another novelty
in the economy of worlds, for with a perpendicular axis of rotation she
can have no succession of seasons, no winter and summer flitting, one
upon the other's heels, to and fro between the northern and southern
hemispheres; but, on the contrary, her climatic conditions must be
unchangeable, and, on any particular part of her surface, except for
local causes of variation, the weather remains the same the year around.
So, as far as temperature is concerned, Venus may have two regions of
perpetual winter, one around each pole; two belts of perpetual spring in
the upper middle latitudes, one on each side of the equator; and one
zone of perpetual summer occupying the equatorial portion of the planet.
But, of course, these seasonal terms do not strictly apply to Venus, in
the sense in which we employ them on the earth, for with us spring is
characterized rather by the change in the quantity of heat and other
atmospheric conditions that it witnesses than by a certain fixed and