ed, my awestruck eyes wandering
over the mysterious tracts of the Milky Way and the familiar
constellations of the mimic heavens. "May I ask how it is done--how you
produce that impression of infinite distance?"

"By means of translucent shells illuminated from behind. The stars, of
course, are electric lamps, and some of them, as you see, have a tinge
of red or blue."

Most of the light, however, came from a brilliant globe of a bluish
lustre, which appeared to occupy the centre of the crystal sphere, and
was surrounded by a number of smaller and fainter orbs that shone by its
reflected rays.

"This, again, is a model of the solar system," said Gazen. "The central
luminary is, of course, the sun, and the others are the planets with
their satellites."

"They seem to float in air."

"That is because their supports are invisible, or nearly so. Both their
lights and periodic motions are produced by the electric current."

"Surely they are not moving now?"

"Oh, yes, and with velocities proportionate to those of the real bodies;
but you know that whilst the actual movements of the sun and planets are
so rapid, the dimensions of the system are so vast that if you could
survey the whole from a standpoint in space, as we are supposed to do,
it would appear at rest. Let us look at them a little closer."

I followed Gazen along the gangway which encircled the orrery, and
allowed us to survey each of the planets closer at hand.

"This kind of place would make a good theatre for a class in astronomy,"
said I, "or for the meetings of the Interplanetary Congress of
Astronomers, in the year 2000. You can turn on the stars and planets
when you please. I wish you would give me a lecture on the subject now.
My knowledge is a little the worse for wear, and a man ought to know
something of the worlds around him--especially if he intends to visit
them."

"I should only bore you with an old story."

"Not at all. You cannot be too simple and elementary. Regard me as a
small boy in the stage of

"'Twinkle, twinkle, little star,
How I wonder what you are!'"

"Very well, my little man, have you any idea how many stars you can see
on a clear night?"

"Billions."

"No, Tommy. You are wrong, my dear boy. Go to the foot of your class.
With the naked eye we can only distinguish three or four thousand, but
with the telescope we are able to count at least fifty millions. They
are thickest in the Milky Way, which, as you