Many Dimensions

"DO you mean," Sir Giles said, "that the thing never gets smaller?"
"Never," the Prince answered. "So much of its virtue has entered into its outward form that whatever may happen to it there is no change. From the beginning it was as it is now."
"Then by God, sir," Reginald Montague exclaimed, "you've got the transport of the world in your hands."
Neither of the two men made any answer. The Persian, sitting back in his chair, and Sir Giles, sitting forward on the edge of his, were both gazing at the thing which lay on the table. It was a circlet of old, tarnished, and twisted gold, in the centre of which was set a cubical stone measuring about half an inch every way, and having apparently engraved on it certain Hebrew letters. Sir Giles picked it up, rather cautiously, and concentrated his gaze on them. The motion awoke a doubt in Montague's mind.
"But supposing you chipped one of the letters off?" he asked. "Aren't they awfully important? Wouldn't that destroy the—the effect?"
"They are the letters of the Tetragrammaton," the Persian said drily, "if you call that important. But they are not engraved on the Stone; they are in the centre—they are, in fact, the Stone."