ere going to
have to do something to build up our muscles again. I supposed I had
lost weight just as much as he had. It would be tough to weigh ourselves
here, since we had only the balance in the laboratory. Spring scales
wouldn't work on the asteroid--we wouldn't have weighed enough to
register, even though our mass was probably about the same as an average
man's on earth.

Red put the book aside, closed his eyes and smiled. My eyes fell on the
book for some reason. Then suddenly I saw a page flip over. I didn't
realize at first that this couldn't happen.

There wasn't any draft in the place, I was sure of that. A draft would
mean a leak in the laboratory and alarms would tell us when that
happened. There was no motion, nothing to cause a page in the book to
turn.

Another page turned and I was sure I wasn't dreaming. I pulled myself
over to the door, opened it a trifle.

"Red!" I called softly.

"Dollie!" He was dreaming. Dollie was one of the dozen or so girls he
was always talking about in his sleep.

I pulled myself to his side and punched him gently. Red woke up. "You're
a hell of a guy," he said.

"Yes," I said. "You were dreaming about Dollie. But I saw something
happen here and I wanted you to see it too." I pointed at the book. The
pages were still now. Suddenly one of them flipped over.

"Somebody, or something is reading your book," I said.

* * * * *

We didn't figure it out then and I wasn't even sure that I'd made the
right diagnosis, but things went on every day afterwards that left me
convinced there was something else living on this hunk of rock besides
Red and me. It didn't have mass, apparently, because we tried our best
to touch it.

Once when it got to fooling around with the laboratory balance, Red and
I encircled the balance with our arms and then squeezed together without
feeling a thing.

It wasn't energy, because we tried every instrument to detect
electricity, heat, light, and radio. But it was alive, because it moved.
It read books and monkeyed with the lab scales.

And at last I decided that maybe _it_ had something to do with the
apparent discrepancy in the asteroid's change in mass. After that I had
a great deal to work on.

Red began behaving queerly too. He swore that he was getting too small
for his clothing. His shoes, he said, were almost a size too large. I
was too busy to check, so I put it down as a loss in weight.

We'd spent