it as well as I ever knew elementary algebra.
Thanks, fellows, a million times--but say, did you leave any open spaces
for more? In one way, I seem to know less than I did before, there's so
much more to find out. Can I learn anything more, or did you fill me up
to capacity?"

The psychologist, who had been listening to the exuberant youth with
undisguised pleasure, spoke calmly.

"The mere fact that you appreciate your comparative ignorance shows that
you are still capable of learning. Your capacity to learn is greater
than it ever was before, even though the waste space has been reduced.
Much to our surprise, Rovol and I gave you all of his knowledge that
would be of any use to you, and some of my own, and still theoretically
you can add to it more than nine times the total of your present
knowledge."

The psychologist departed, and Rovol and Seaton returned to the
laboratory, where the forces were still merrily at work. There was
nothing that could be done to hasten the connecting, and it was late in
the following period of labor before they could begin the actual
construction of the projector. Once started, however, it progressed with
amazing rapidity. Now understanding the system, it did not seem strange
to Seaton that he should merely actuate a certain combination of forces
when he desired a certain operation performed; nor did it seem unusual
or worthy of comment that one flick of his finger over that switchboard
would send a force a distance of hundreds of miles to a factory where
other forces were busily at work, to seize a hundred angle-bars of
transparent purple metal that were to form the backbone of the
fifth-order projector. Nor did it seem peculiar that the same force,
with no further instruction, should bring these hundred bars back to
him, in a high loop through the atmosphere; should deposit them gently
in a convenient space near the site of operations; and then should
disappear as though it had never existed! With such tools as that, it
was a matter of only a few hours before the projector was done--a task
that would have required years of planning and building upon Earth.

Two hundred and fifty feet it towered above their heads, a tubular
network of braced and latticed bars of purple metal, fifty feet in
diameter at the base and tapering smoothly to a diameter of about ten
feet at the top. Built of a metal thousands of times as strong and hard
as steel, it was not cumbersome in appearance, and y