I knew that, if my hunch failed, I’d have a lot to answer for when she followed me and stood in the doorway, ready to pounce.

There was a bunch of junk from the Trader standing on the desk and a lot more of it in one corner. I cleared off the desk and that was when Bill came in.

“What you doing, Dad?” he asked.

“Your father’s gone insane,” Helen explained quietly.

They stood there, watching me, while I took a handful of dirt and sprinkled it on the desk top.

It stayed there for just an instant—and then it was gone. The top of the desk was spotless.

“Bill,” I said, “take one of those gadgets out to the garage.”

“Which one?”

“It doesn’t matter.”

So he took one and I spread another handful of dirt and, in a second, it was gone.