“You mean that he worked out a code message somewhere?”
“Exactly.”
“Then it must be in that rock wall!”
“Exactly. Remember he had all of those different rocks brought in from the desert.”
Della Street’s eyes sparkled. “And I suppose that means we’re going to be the first ones to throw a beam of invisible light on that wall and see what the message is?”
“We’re going to try to be first,” Mason said.
“But the prowler must have been using one of these machines.”
Mason was thoughtful. “The machine may have been one that Salty Bowers or Banning Clarke was using at a place on the wall a short distance from where Velma saw the prowler. The prowler may have been trying to find out what was going on. In any event, I think we’ve found an explanation for the drowsy mosquito.”
Chapter 20
It was too early for the distorted moon to lift itself over the horizon. For the moment, the night was dark save for the stars which, in this ocean-misted atmosphere, seemed distant, impersonal pin points.
Della Street held the flashlight. Mason carried the long, boxlike apparatus for generating black light. The house at the north end of the big grounds was silhouetted against the night as a dark rectangle. There was no sign of human occupancy anywhere in the building.
Mason took up a position some ten feet from the wall.
“All right, Della,” he said, “let’s have it dark.”
She snapped out the flashlight.
Mason turned a switch. From the interior of the box came a low, distinctive hum, and a moment later, the darkness of the night seemed to turn slightly luminous and a deep violet.
Mason directed the rays of ultraviolet light against the wall. Almost instantly a series of colored lights winked back at him. In silence the lawyer and Della Street studied them.
“Do you make anything out of it, Chief?” she asked anxiously.
Mason didn’t answer immediately. When he did, there was discouragement in his tone. “Not a darn thing. Of course, it may be in some sort of code... It’s just a succession of isolated dots. There doesn’t seem to be any particular pattern.”
Mason moved on down the wall. “Looks pretty hopeless,” he remarked, and Della’s keen ears could detect the disappointment in his voice, showing to what extent he had banked on his theory.
“Perhaps it’s something else that has to do with this ultraviolet light,” she said, knowing how much it meant to them, and realizing that Mason was in a predicament from which he could extricate himself only by quick, clear thinking and that solving the mystery of the drowsy mosquito was but the first step. Failing in that, they were beaten on everything else.
“I can’t imagine what it could be. The deuce of it is, Della, we’re working against time... Hello, what’s this!”
Mason had been moving down the wall, coming to the lower portion where the wall tapered down until it was hardly four feet high.
“It’s a straight line,” Della exclaimed. “Those fluorescent stones have been arranged so they make a straight line, and over here— Oh, look!”
Mason had swung the portable light over to the left so that an entirely new section of wall was brought into their field of vision. A whole series of luminous lines appeared, as though someone had etched a roughly rectangular diagram with a phosphorescent pencil.
Della said, “There’s some kind of flower with pointed petals. It’s hanging upside down.”
Mason frowned as he looked at the object: apparently a five-petaled flower, hanging downward from a slightly curved stem. Abruptly he exclaimed, “By George!”
“What?” Della asked.
“The Shooting Star,” Mason said in low tones. “That’s not a flower hanging upside down — it’s a shooting star, and those lines must be the boundaries of the claims, and this cross must mark the point where Banning Clarke discovered the evidence showing it’s the original Goler discovery.”
“That’s it,” Della exclaimed, excitedly. “Gosh, Chief, I feel as though we’d just located a valley full of gold. My knees are all trembly.”
Mason, apparently thinking out loud, said, “That’s why he wanted to put up a fight on the fraud case. You can see his position, Della. If he tried to get any property back from the mining company, that would be the pay-off — the clue that would enable Bradisson to go and locate the lost Goler claim. But, by pretending he was trying to beat a hopeless case, and trying to keep Mrs. Sims from getting her claims back, Clarke managed to pull the wool over everyone’s eyes — including my own.”
“Then Mrs. Sims will get her claims back?” Della asked.
“Hang it,” Mason muttered with exasperation, “I fixed it so she won’t. I trapped Bradisson on his deposition into making statements that changed that fraud case from a hopeless case to an ironclad cinch — and by doing it, deprived my client of a fortune. Now I’ve got to find some way of executing a legal flip-flop before they get wise to the real value... And there’s always the possibility someone else knows about this.”
“About the Shooting Star and the secret of the drowsy mosquito?”
“Yes.”
“You mean the prowler?”
“Yes.”
“But don’t you think the prowler was simply spying on Banning Clarke who was using the light to help arrange the rocks in the wall? And the prowler may have been frightened away before he learned the secret? After all, Banning Clarke could have stripped off his outer garments after he heard the shots the prowler fired.”
“That’s right,” Mason said. “But remember that this prowler could always come back. He shot after Velma had seen him, but to keep her from turning the flashlight on him. Therefore, he shot, not to prevent discovery but recognition, and—”
“Someone’s coming!” Della exclaimed.
“Quick, Della. We can’t afford to be caught here. Lucky we left our car away from the house.” Mason started around behind the cacti looking for a place of concealment as two dazzling headlights came crawling through the gate and turned into the driveway.
Della Street came to stand at his side, and Mason could feel her fingers digging into his arm as they stood waiting breathlessly.
The car rattled to a stop.
The motor quit its tin-pan rhythm. The headlights snapped off. After a moment, they heard the car doors open and then bang shut.
“Probably Salty coming back,” Della whispered. “Sounds like his car.”
“Wait a minute,” Mason cautioned in a low voice.
They heard Nell Sims saying, “Now then, Pete Sims, you march right in to that pantry. If you’ve made my daughter poison Banning Clarke, I’m going to lift the scalp right off your head.”
Pete’s voice had that pleading, apologetic whine which was so characteristic of him in his moments of explanation. “I tell you, honey, you don’t know anything about a man’s business. Now this mining business...”
“I know enough to know that when a man gives his wife arsenic to put in the pantry alongside the sugar bowl, he’s just crazy.”
“But listen, honey, I...”
The sound of the side door of the house opening and shutting swallowed the rest of the conversation.
Mason bent down, shoved the long box back under the heavy growth of a thick clump of spineless cactus. “We’ve got to see him, Della.”