Here I found, to my surprise, a gem of a world which I will call Holen.
It is five hundred miles in diameter, and inhabited by a refined race of
human beings, radically different from us in physical contour, but
remarkably similar to us in their mental aspirations.

As a race they greatly excel us in mechanical engineering. Many
evidences of their skill might be given, but we will be content to give
a description of their monumental engineering feat.

Long ages ago Holen had cooled to the center, and it became the ruling
passion of her most intelligent inhabitants to communicate from one
side of the globe to the other through an opening of five hundred miles
almost directly through the center of their earth, or more accurately
speaking, through the center of gravity.

After forty-five hundred years of experimenting the marvelous feat was
accomplished.

Of all the worlds in the constellation of Orion, large or small, Holen
is the only one that has succeeded in this astounding feat, although it
has been and is being tried on more than a dozen worlds.

This wonderful opening through Holen's center of gravity is lined with
sections of ribbed metal which cost the governments fabulous sums. This
vast tube was finished thirteen hundred years ago according to our time.

Many lives were sacrificed in the hazardous work of tunneling. Were it
not for the ribbed metal which afforded protection with its shelving
flanges, the tube could never have been finished.