of fine vertical scratches marred every inch
of her surface, and here and there the stubborn metal was grooved and
scored to a depth of inches--each scratch and score the record of an
attempt of some wandering cosmic body to argue the right-of-way with
the stupendous mass of that man-made cruiser of the void.

A burly young man made his way through the throng about the entrance,
nodded unconcernedly to the gatekeeper, and joined the stream of
passengers flowing through the triple doors of the double air-lock
and down a corridor to the center of the vessel. However, instead of
entering one of the elevators which were whisking the passengers up to
their staterooms in the upper half of the enormous football, he in some
way caused an opening to appear in an apparently blank steel wall and
stepped through it into the control room.

"Hi, Breck!" the burly one called, as he strode up to the instrument-desk
of the chief pilot and tossed his bag carelessly into a corner. "Behold
your computer in the flesh! What's all this howl and fuss about poor
computation?"

"Hello, Steve!" The chief pilot smiled as he shook hands cordially.
"Glad to see you again--but don't try to kid the old man. I'm simple
enough to believe almost anything, but some things just aren't being
done. We have been yelling, and yelling hard, for trained computers
ever since they started riding us about every one centimeter change in
acceleration, but I know that you're no more an I-P computer than I am
a Digger Indian. They don't shoot sparrows with coast-defense guns!"

[Illustration]

"Thanks for the compliment, Breck, but I'm your computer for this trip,
anyway. Newton, the good old egg, knows what you fellows are up against
and is going to do something about it, if he has to lick all the rest of
the directors to do it. He knew that I was loose for a couple of weeks
and asked me to come along this trip to see what I could see. I'm to
check the observatory data--they don't know I'm aboard--take the peaks
and valleys off your acceleration curve, if possible, and report to
Newton just what I find out and what I think should be done about it.
How early am I?" While the newcomer was talking, he had stripped the
covers from a precise scale model of the solar system and from a large
and complicated calculating machine and had set to work without a wasted
motion or instant--scaling off upon the model the positions of the
various check-stations and setting up lon