“Which one?”

“It doesn’t matter.”

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

Bill was back by that time and I sent him out with another gadget.

We kept on like that for quite a while and Bill was beginning to get disgusted with me. But finally I sprinkled the dirt and it stayed.

“Bill,” I said, “you remember the last thing you took out?”

“Sure.”

“Well, go out and bring it back again.”

He got it and, as soon as he reached the door of the den, the dirt disappeared.

“Well, that’s it,” I said.

“That’s what?” asked Helen.

I pointed to the contraption Bill had in his hand. “That.

Throw away your vacuum cleaner. Burn up the dustcloth.

Heave out the mop. Just have one of those in the house and…”

She threw herself into my arms.

“Oh, Joe!”

We danced a jig, the two of us.

Then I sat around for a while, kicking myself for tying up with Lewis, wondering if maybe there wasn’t some way I could break the contract now that I had found something without any help from him. But I remembered all those clauses we had written in. It wouldn’t have been any use, anyhow, for Helen was already across the street, telling Marge about it.

So I phoned Lewis at the lab and he came tearing over.

We ran field tests.

The living-room was spotless from Bill just having walked through it, carrying the gadget, and the garage, where he had taken it momentarily, was spick-and-span. While we didn’t check it, I imagine that an area paralleling the path he had taken from the front door to the garage was the only place outdoors that didn’t have a speck of dust upon it.

We took the gadget down in the basement and cleaned that up. We sneaked over to a neighbour’s back yard, where we knew there was a lot of cement dust, held the gadget over it and in an instant there wasn’t any cement dust. There were just a few pebbles left and the pebbles, I suppose, you couldn’t rightly classify as dust.