a
jeep, he probably would do so right away. Otherwise, why should he be
the first to leave the dining room?

"Why would anyone steal dynamite?" Rick asked the police officer. He
wanted only to keep a quiet conversation going behind the pump house.

The officer had theories. Perhaps revolutionaries had stolen it. Also,
although it was against the law and brought severe punishment, fishermen
were known to dynamite fish. This also was a possibility. But the
explosion of the dynamite on the mountainside was certainly a puzzle.

Rick didn't think so, but he agreed politely. It was bewildering, he
said. Why steal explosives and then use it on a harmless scientific
group?

Perhaps fear of discovery caused the thief to set a trap, the officer
guessed. He admitted it wasn't a good guess.

A jeep roared into life and the boys stiffened. The officer strolled out
of the shadow for a look. "One of your associates is going for a ride,"
he said.

Rick waited until the jeep lights cut across the parking lot and moved
down the western road, then he said, "It's a nice night for a ride,
Scotty. What say we take a jeep and look over the country, too?"

"Good idea," Scotty agreed readily.

They bade the officer good night and started to where Zircon's jeep was
parked. It was a temptation to hurry, but they suppressed it and
sauntered to the jeep. Fortunately, no keys were needed. The jeep
ignition was turned on by a simple switch. Rick got into the driver's
seat and started up. He waited, the motor idling, until he was sure
Connel was out of sight around the mountain, then he drove slowly across
the parking lot and followed.

Fortunately, there was enough moonlight to see the road. Once out of
sight of the hotel, Rick stopped and switched off the lights. As his
eyes adjusted to the dimness he started off again as fast as vision
allowed.

Once he sighted Connel's lights. They were ahead and higher on the
mountain. He lost sight of them again as foliage blocked the view.
"Suppose he's heading for the shot station?" he asked.

Scotty shrugged. "We'll soon know."

They reached the pumice works without seeing the geologist's lights
again, and Rick stopped at the turnoff. "Now what?" he asked. "Did he go
up the trail or not?"

Scotty sniffed the air. "Smell anything?"

Rick breathed deeply. There was the odor of rank vegetation, and, very
faintly, the odor of sulfur from the hot springs. But there was another
smell, too. After