art will know
what I mean.'"

"That's crazy. I don't know--"

He broke off, for the memory had come, full-blown:

_He was very young: five, six, seven. His mother, tall and slender and
very fair, was bending over a blueprint, pointing with a delicate finger
at something, straightening, saying in her light musical voice:_

_"The fuel catalyst--it's a strange color, a color you never saw
anywhere. Can you_ think _of a color that isn't red, orange, yellow,
green, blue, violet, indigo or some combination of them? It isn't any of
the colors of the spectrum at all. The fuel is a real eighth color."_

_And his father had used the phrase, almost adopted it. "When we know
what the eighth color is, we'll have the secret of the star-drive,
too!"_

Briscoe saw his face change, nodded weakly. "I see it means something to
you. Now will you do as I tell you? Within a couple of hours, they'll be
combing the planet for you, but by that time the ship I came in on will
have taken off again. They only stop a short time here, for mail,
passengers--no cargo. They may get under way again before all messages
are cleared and decoded." He stopped and breathed hard. "The Earth
authorities might protect you, but you would never be able to board a
Lhari ship again--and that would mean staying on Earth for the rest of
your life. You've got to get away before they start comparing notes.
Here." His hand went into his pockets. "For your hair. It's a dye--a
spray."

He pressed a button on the bulb in his hand; Bart gasped, feeling cold
wetness on his head. His own hand came away stained black.

"Keep still." Briscoe said irritably. "You'll need it at the Procyon end
of the run. Here." He stuck some papers into Bart's hand, then punched
some buttons on the robotcab's control. It wheeled and swerved so
rapidly that Bart fell against the fat man's shoulder.

"Are you crazy? What are you going to do?"

Briscoe looked straight into Bart's eyes. In his hoarse, sick voice, he
said, "Bart, don't worry about me. It's all over for me, whatever
happens. Just remember this. What your father is doing is _worth_ doing,
and if you start stalling, arguing, demanding explanations, you can foul
up a hundred people--and kill about half of them."

He closed Bart's fingers roughly over the papers. The robotcab hovered
over the spaceport. "Now listen to me, very carefully. When I stop the
cab, down below, jump out. Don't stop to say good-bye, or ask questions,