echnical nature.

One day she bluntly asked him how he knew what he was doing.

James grinned. "I really _don't_ know what I'm doing," he admitted. "I'm
only following some very explicit directions. If I knew the pure theory
of my father's machine I could not design the instrumentation that would
make it work. But I can build a reproduction of my father's machine from
the directions."

"How can that be?"

James stopped working and sat on a packing case. "If you bought a
lawn-mower," he said, "it might come neatly packed in a little box with
all the parts nested in cardboard formers and all the little nuts and
bolts packed in a bag. There would be a set of assembly directions,
written in such a way as to explain to anybody who can read that Part A
is fastened to Bracket B using Bolt C, Lockwasher D, and Nut E. My
father's one and only recognition of the dangers of the unforeseeable
future was to drill deep in my brain these directions. For instance," and
he pointed to a boxed device, "that thing is an infra-low frequency
amplifier. Now, I haven't much more than a faint glimmer of what the
thing is and how it differs from a standard amplifier, but I know that it
must be built precisely thus-and-so, and finally it must be fitted into
the machine per instructions. Look, Mrs. Bagley." James picked up a
recently-received package, swept a place clear on the packing case and
dumped it out. It disgorged several paper bags of parts, some large
plates and a box. He handed her a booklet. "Try it yourself," he said.
"That's a piece of test equipment made in kit form by a commercial outfit
in Michigan. Follow those directions and build it for me."

"But I don't know anything about this sort of thing."

"You can read," said James with a complete lack of respect. He turned
back to his own work, leaving Mrs. Bagley leafing her way through the
assembly manual.

To the woman it was meaningless. But as she read, a secondary thought
rose in her mind. James was building this devilish-looking nightmare, and
he had every intention of using it on her daughter! She accepted without
understanding the fact that James Holden's superior education had come of
such a machine--but it had been a machine built by a competent mechanic.
She stole a look at James. The anomaly puzzled her.

When the lad talked, his size and even the thin boyish voice were negated
by the intelligence of his words, the size of his vocabulary, the clarity
of his statem