covered electronics, astrophysics, astrogation, and allied fields. Astro
took charge of rockets, missiles, power machinery, and applied uses of
atomic energy. Jeff's work was biological, bacteriological,
mineralogical, and geological. Tom covered social studies, government,
economy, and history.

Resting as comfortably as possible, each of the four spacemen would sit
and think. And when he had gone as far back as he could in his memory of
formal education and acquired knowledge, he would begin to talk into the
soundscriber. Of all the spools, Tom's were edited the least. And
Professor Sykes had unbent enough to compliment the curly-haired cadet
for his lucid thinking and acute memory. Astro's work needed the most
editing. The giant Venusian found it difficult to explain what he did
when he repaired atomic power plants, or how he could look at a piece of
machinery and know instinctively when it was out of order. He worked
twice as hard as the others, simply because Sykes made him do everything
over.

On the other hand, Roger sailed along as smoothly as a jet boat. His
grasp of the fundamentals in his field made it easy for him to fill the
study spools with important information. Jeff, too, found it easy to
explain the growth of plants, the function of bacteria, the formation of
planet crusts, and other allied subjects.

So, day after day, Tom, Astro, Roger, and Jeff Marshall spent their
waking hours in the cubicles searching their minds for every last
precious drop of knowledge they could impart to the children of Roald.

Vidac's warning to Professor Sykes to keep an eye on Roger had been
forgotten by everyone in the concerted effort to do a good job. And when
the cadets and Jeff left their work one night after a loud argument
between the professor and Roger over the best way to explain the theory
of captive planets, they thought nothing of it. The argument hadn't been
unusual. It had happened many times on the same score. Professor Sykes
was prone to favor dry, factual explanations. And the cadets believed
some of the theories needed explanations in terms a youngster could
understand. Sykes did not object to this method, but was wary of losing
facts and clarity in the method of instruction. In this particular case,
Roger had given in to Sykes, but only after a heated argument. And when
they went back to their quarters, there was none of the usual
discussion. They were too tired. They fell asleep as soon as their hea