But we are ready to test it—a practical test. Tonight, Frank, my boy Brett is going upon an adventure"
The fear which had been lurking in his eyes leaped to stamp his other features. He was afraid for Brett—afraid of this thing they were going to do. He had stopped abruptly; and more quietly he added:
"I want you to understand me, Frank, and so for a moment we must be wholly theoretical. This thing we are about to do involves the construction of our whole material universe. You know, of course, that no limit has been found to the divisibility of matter?"
His sudden question confused me. "You mean," I stammered, 44that things can be infinitely small?"
"That there is no limit to smallness," Brett put in. "An atom—an electron—they are mere words. Within them conceivably might be a space with stars, planets, suns—worlds of their own so tiny that compared to the Space in which they roam that Space would seem—and would be—illimitable. Picture that, Frank. And picture upon one of those worlds inhabitants of proportionate smallness. What would they see, feel or think of the universe? Would they not conceive it about as we do? Picture them with powerful microscopes, looking downward into the matter composing their world. They would be aware of molecules, atoms—they would gaze down into Space unending. Another realm within their own. And within that one—others and yet others to infinity. The conception confuses you, Frank? It need not. Each of those realms is tiny—or large—according to the viewpoint. There can be no such thing as absolute size."
"That is what I mean," Dr. Gryce interrupted eagerly. "Absolute size—how can you conceive it? You can not. A thing is large or small only in relation to something else smaller or larger."
He waved his hand to the rolling landscape with the morning light and shadow upon it, visible through the arbor.
"There is our everyday world, Frank. How big is it? You can not say. Millimeters, meters, kilometers, helans, light-years—those are only words with which we designate a comparison. Compared to what our microscopes show us, this world of ours is* very large, but compared to the spaces between the stars—the stars themselves—it is very small. Try then to imagine its absolute size. You can not, because there is no such thing. A universe within what we call an atom—another realm within an atom of matter upon one of the worlds of that universe—is not an extraordinary state of smallness until we compare it with ourselves.
"And this world of ours. It is normal to us; of no absolute size whatever—neither large nor small—until we compare it to something else. But suppose we visualize larger realms? Suppose we say these planets, stars—all the starry universe within our ken and this visual space which contains them—suppose we imagine all that to be contained within the atom of a particle of matter of some comparatively still larger realm? At once our world and ourselves shrink into smallness. Where a moment ago we had seemed large, now we seem small. Yet that other gigantic world within which we are contained—if we could live in it our telescopes would show us still larger Space unending. We would feel tiny—and of actuality we would be tiny—contemplating Space and size so much larger."
"And there you have infinity of Space," Brett added, as his father paused. "Unending Space both smaller and larger than ourselves. We—everything of which we can be
