coming from the exhaust. Without bothering to take down the plastic
Sun-shield, Burl and Boulton tumbled into the cabin. Before the door
was even closed, Haines lifted the ship and headed for the dark depths
of the canyon.

The inside of the plane was perilously hot. The shield had been a
temporary protection, but even the ground radiated heat like an oven.
They had to seek the cold of the sunless canyon to allow some of the
heat to escape. To have flown directly to the _Magellan_ without cooling
the plane would have been disastrous.

The _Magellan_ emerged from the cold side to meet them. From the heights
of space, they saw that they would not need to bomb the mountain relayer
masts--for the same alarm that had triggered the station had shattered
them.

After the _Magellan_ had scuttled back to the cold side, there was a
council of war in the control room. Burl and Boulton described very
carefully what had happened.

"This must have been their primary station," said Russ thoughtfully. "No
matter what they seek to channel from the Sun on other planets, it is
from here that the first and strongest diversion of solar energy must
have been coming. This station may have been the last constructed--the
final link put into place. And for that reason, they installed an
alarm."

"Ah," said Lockhart, "even if they did, would it necessarily have
destroyed the station? After all, they would normally have figured on
repairing whatever went wrong."

"It seems to me," said Burl, "that the red flash itself didn't start the
destruction. There was a delay--must have been several minutes--before
it started. Could it be, that what was alerted was a watcher?"

"Where?" said Boulton. "There was no place for a watcher to be in that
station. We saw no sign of it."

"Maybe deep underground?" suggested the engineer, Caton. "They might
have living quarters a few miles underneath."

"Highly unlikely," said Russ Clyde. "It would still be too hot, and,
remember, these people plan to incinerate Mercury and the inner planets.
They must be from the edge of the system. The delay may be a valuable
clue to that. It would take time for a remote control station on another
planet to see what was happening and take steps. If you can figure out
exactly how many minutes and seconds elapsed between the flashing of the
red bulb and the blowup, we could work out the approximate distance."

But, unfortunately, the time could not be judged that accurat