“This will answer, Hawkins.”

“Yes, sir,” said Hawkins impassively.

And if I realize that Sperry was nervous that night, I also realize that he was fighting a battle quite his own, and with its personal problems.

“She’s got to quit this sort of thing,” he said savagely and apropos of nothing, as we walked along.  “It’s hard on her, and besides—­”

“Yes?”

“She couldn’t have learned about it,” he said, following his own trail of thought.  “My car brought her from her home to the house-door.  She was brought in to us at once.  But don’t you see that if there are other developments, to prove her statements she —­well, she’s as innocent as a child, but take Herbert, for instance.  Do you suppose he’ll believe she had no outside information?”

“But it was happening while we were shut in the drawing-room.”

“So Elinor claims.  But if there was anything to hide, it would have taken time.  An hour or so, perhaps.  You can see how Herbert would jump on that.”

We went back, I remember, to speaking of the seance itself, and to the safer subject of the physical phenomena.  As I have said, we did not then know of those experimenters who claim that the medium can evoke so-called rods of energy, and that by its means the invisible “controls” can perform their strange feats of levitation and the movement of solid bodies.  Sperry touched very lightly on the spirit side.

“At least it would mean activity,” he said.  “The thought of an inert eternity is not bearable.”

He was inclined, however, to believe that there were laws of which we were still in ignorance, and that we might some day find and use the fourth dimension.  He seemed to be able to grasp it quite clearly.  “The cube of the cube, or hypercube,” he explained.  “Or get it this way:  a cone passed apex-downward through a plane.”

“I know,” I said, “that it is perfectly simple.  But somehow it just sounds like words to me.”

“It’s perfectly clear, Horace,” he insisted.  “But remember this when you try to work it out; it is necessary to use motion as a translator of time into space, or of space into time.”

“I don’t intend to work it out,” I said irritably.  “But I mean to use motion as a translator of the time, which is 1:30 in the morning, to take me to a certain space, which is where I live.”

But as it happened, I did not go into my house when I reached it.  I was wide awake, and I perceived, on looking up at my wife’s windows, that the lights were out.  As it is her custom to wait up for me on those rare occasions when I spend an evening away from home, I surmised that she was comfortably asleep, and made my way to the pharmacy to which the Wellses’ governess had referred.

The night-clerk was in the prescription-room behind the shop.  He had fixed himself comfortably on two chairs, with an old table-cover over his knee and a half-empty bottle of sarsaparilla on a wooden box beside him.  He did not waken until I spoke to him.