al to the square root
of the pressure-head driving it. But when you actually put things
together, contractions or expansions in the gas, surface roughness and
other factors make the velocity a bit smaller.

At the terrible discharge speed of nuclear explosion--which is what the
drive amounts to despite the fact that it is simply water in which
nuclear salts have been previously dissolved--this small factor makes
quite a difference. I had to figure everything into it--diameter of the
nozzle, sharpness of the edge, the velocity of approach to the point of
discharge, atomic weight and structure-- Oh, there is so much of this
that if you're not a nuclear engineer yourself it's certain to weary
you.

Perhaps you had better take my word for it that without this
equation--correctly stated, mind you--mankind would be well advised not
to make a first trip to the moon. And all this talk of coefficients and
equations sits strangely, you might say, upon the tongue of a man named
Kevin Francis Houlihan. But I am, after all, a scientist. If I had not
been a specialist in my field I would hardly have found myself engaged
in vital research at the center.

Anyway, I heard these little noises in the park. They sounded like small
working sounds, blending in eerily mysterious fashion with a chorus of
small voices. I thought at first it might be children at play, but then
at the time I was a bit absent-minded. I tiptoed to the edge of the
trees, not wanting to deprive any small scalawags of their pleasure, and
peered out between the branches. And what do you suppose I saw? Not
children, but a group of little people, hard at work.

There was a leader, an older one with a crank face. He was beating the
air with his arms and piping: "Over here, now! All right, bring those
electrical connections over here--and see you're not slow as treacle
about it!"

There were perhaps fifty of the little people. I was more than startled
by it, too. I had not seen little people in--oh, close to thirty years.
I had seen them first as a boy of eight, and then, very briefly again,
on my tenth birthday. And I had become convinced they could _never_ be
seen here in America. I had never seen them so busy, either. They were
building something in the middle of the glade. It was long and shiny and
upright and a little over five feet in height.

"Come along now, people!" said this crotchety one, looking straight at
me. "Stop starin' and get to work! You'll not b