oon."

Fortunately, the Miller farm was well equipped with boots and overshoes.
The boys borrowed footgear suitable for any mud left by the rain and
started out after lunch.

The picnic area was washed clean of footprints and it was clear no one
had visited the area since the rain. They made their way to the top of
the hill above the mine and surveyed the cornfield that had been planted
on the hilltop field. The corn was not high. The plants came only to
their knees. Either it was a second planting or a poor crop. Rick
guessed that the second reason was probably the correct one, because the
field hadn't been cultivated recently.

"This isn't Miller land," he mused. "Wonder who is farming it?"

"It must be Hilleboe's property," Scotty returned. "Maybe he rents it to
some local farmer."

They walked to the downstream edge of the cornfield to where the woods
resumed. Rick had a feeling that they were wasting time. The ghost
couldn't be produced from such a distance by any means he had ever heard
of. The apparition had to be created right in the vicinity of the mine.

He spoke his thoughts aloud, and added, "Let's go back."

"Just a minute." Scotty pointed to a pile of brush. "Aren't those more
bags?"

They were, and of the same brand as those the boys had located on the
stream bank. Scotty picked one up and tested it between his fingers.
"Mighty curious. Water cures Portland cement. Turns it hard. These bags
aren't hard, even though some powder is still in them."

Rick examined the bags, his brows creased with bewilderment. "They must
have held something besides cement. But what? Fertilizer for the
cornfield, maybe? And why two caches?"

"If it were fertilizer, the bags near the mine could have been for the
field across the creek where the plane is," Scotty suggested. "These
could have been for this field. But I don't think it was fertilizer.
Isn't fertilizer soluble in water?"

Rick wasn't sure. "We can take the bag along," he said. "Maybe the
microscope will tell us something, or maybe Dr. Miller will know."

He had a feeling that the bags meant something. They had been hidden,
and only the erosion of rain had uncovered them, first at the creek
embankment and now here. The Frostola man had almost certainly taken the
others. Why? Unless they had something to do with the mystery? The bags
were worthless, of themselves.

They finished the survey of the area. It was clear that whoever produced
the ghost would