“I remember the Professor - the whole of him —standing over me and talking excitedly. I looked up in a dazed and bewildered fashion : he was waving his arms about, and crying that he had Found the Way: then suddenly he thrust his hand as it were through a hole in space ; for it vanished completely: he deliberately plunged his arm up to the elbow in —nothing ; and drew it out again.”

[...]

But it’s so easy,” he kept on repeating; “ easy as winking. Why didn’t I ever think of it before? ”

“Think of what?” I asked desperately.

“The Fourth Dimension,” he answered. “Here have we been fooling around after Imaginary Roots, and Functions, trying to mop up the mess Einstein has made, when all the time the Fourth Dimension was no different in kind from the other three that we are familiar with.”

“But I don’t see."

“No, of course you don’t!” he barked, and settled into the full stride of his lecture-room manner. “ My assumption is that the Fourth Dimension is just another dimension : no more different in kind from length, say, than length is from breadth and thickness : but perpendicular to all three. Now suppose that a being in two dimensions— a flat creature, like the moving shadows of a cinematograph—were suddenly to grasp the concept of the Third Dimension, and so step out of the picture. He might only move an inch, but he would vanish completely from the sight of the rest of his world.”

[...]

I could contain myself no longer. “This is wonderful!” I cried. “This is power ! Think of it! A step, and you are invisible ! No prison cells can hold you, for there is a side to you on which they are as open as a wedding-ring ! No safe is secure from you : you can put your hand round the comer, and draw out what you like. And, of course, if you looked back on the Universe you had left, you would see us in sections, open to you ! You could place a stone or a tablet of poison right in the very bowels of your enemies !”