* * * * *

It was three o'clock the following afternoon when Seaton appeared in the
laboratory. His long rest had removed all the signs of overwork and he
was his alert, vigorous self, but when Crane saw him and called out a
cheery greeting he returned it with a sheepish smile.

"Don't say anything, Martin--I'm thinking it all, and then some. I made
a regular fool of myself last night. Went to sleep in a chair and slept
seventeen hours without a break. I never felt so cheap in my life."

"You were worn out, Dick, and you know it. That sleep put you on your
feet again, and I hope you will have sense enough to take care of
yourself after this. I warn you now, Dick, that if you start any more of
that midnight work I will simply call Dorothy over here and have her
take charge of you."

"That's it, Mart, rub it in. Don't you see that I am flat on my back,
with all four paws in the air? But I'm going to sleep every night. I
promised Dottie to go to bed not later than twelve, if I have to quit
right in the middle of an idea, and I told her that I was coming out to
see her every other evening and every Sunday. But here's the dope. I've
got that missing factor in my theory--got it while I was eating
breakfast this afternoon."

"If you had eaten and slept regularly here and kept yourself fit you
would have seen it before."

"Yes, I guess that's right, too. If I miss a meal or a sleep from now on
I want you to sand-bag me. But never mind that. Here's the explanation.
We doped out before, you know, that the force is something like
magnetism, and is generated when the coil causes the electrons of this
specially-treated copper to vibrate in parallel planes. The knotty point
was what could be the effect of a weak electric current in liberating
the power. I've got it! It shifts the plane of vibration of the
electrons!"

"It is impossible to shift that plane, Dick. It is fixed by physical
state, just as speed is fixed by temperature."

"No, it isn't. That is, it usually is, but in this case it may be
shifted. Here's the mathematical proof."

So saying, Seaton went over to the drafting table, tacked down a huge
sheet of paper, and sketched rapidly, explaining as he drew. Soon the
two men were engaged in a profound mathematical argument. Sheet after
sheet of paper was filled with equations and calculations, and the table
was covered with reference books. After two hours of intense study and
hot disc