f the comet and found this same line
strongly present, we would have a good case for proving the comet was
the source of this substance."

"Let's have a try," said Vickers. "I don't know how successfully we can
get a spectrograph of the comet, but it's worth an attempt."

Their time was short, before the comet vanished below the horizon for
the night. They called for help from the other boys and moved the
equipment to the roof, using the small, portable 6-inch telescope
belonging to the physics department.

There was time for only one exposure. After the sun had set, and the
comet had dropped below the horizon, they came out of the darkroom and
placed the prints in the viewing instrument.

Vickers moved the adjustments gently. After a time he looked up at the
circle of boys. "You were right, Ken," he said. "Your hunch was right.
The comet is responsible. Our engines have been stopped by dust from the
stars."

Chapter 8. _Attack_

There are people who feed upon disaster and grow in their own particular
direction as they would never have grown without it, as does the queen
bee who becomes queen only because of the special food prepared by the
workers for her private use.

Such a man was Henry Maddox. He would not have admitted it, nor was he
ever able to realize it, for it violated the very principles he had laid
down for Ken. But for him, the comet was like a sudden burst of purpose
in his life. He had taught well in his career as professor of chemistry
at the State Agricultural College at Mayfield, but it had become fairly
mechanical. He was vaguely aware of straining at the chains of routine
from time to time, but he had always forced himself through sheer
exercise of will to attend to his duties. There was never time, however,
for any of the research he used to tell himself, in his younger days, he
was going to do.

With the sudden thrusting aside of all customary duties, and with the
impact of catastrophe demanding a solution to a research problem, he
came alive without knowing what was happening. Yet without the imminence
of disaster he would not have found the strength to drive himself so.
This was what he could not admit to himself.

Another who was nourished was Granny Wicks. She should have been dead
years ago. She had admitted this to herself and to anyone else who would
listen, but now she knew why she had been kept alive so long past her
time. She had been waiting for the comet.

Its ener