The Mystery at Bob-White Cave

of Slim.”
    Uncle Andrew, evidently impressed by the respect the Bob-Whites showed for one another, said, “It’s up to you. Tell Slim or don’t tell him. What I want him to do is to guide you and to point out any danger.”
    “Maybe we’ll want to limit it to that,” Trixie said, relieved.
    Several times Brian and Jim asked Linnie to stop the mules while they looked at limestone and clay strata exposed on the jagged cliffs. They explained that each layer of different color represented an era in geological history, and they added that they wanted to do some exploring for minerals.
    “You won’t get a reward for that,” Trixie said. “I’m in favor of devoting all our time to hunting the ghost fish.”
    “We can do both at the same time,” Brian said quietly. “You forget sometimes, Trixie, about the rock collection Jim and I are trying to get together for the clubhouse.”
    “Some rock collections can be as valuable as fish specimens,” Jim added.
    “You’re not serious, are you?” Trixie asked. “I never heard of anyone being offered five hundred dollars for a rock.”
    “It could mean more money than that,” Jim answered, “if, for instance, we could find a deposit of celestite.”
    “What is celestite?” Trixie asked.
    “A soluble mineral used in preparing strontium.”
    “All I know about strontium is that it has something to do with nuclear weapons.”
    “That’s enough to know,” Brian said.-“We’re not likely to find celestite, but it’s only one of many minerals we could find when we gather rock specimens.”
    “Don’t look so discouraged,” Jim was quick to add.
    ‘We’re really on the prowl for the ghost fish.”
    Trixie’s face cleared.
    “We’re at the top of the hill that leads to the lodge,” Linnie said, “but it’s too late now to go cave hunting,
    Trixie, even if Slim has shown up.”
    Slim had shown up.
    When the Bob-Whites piled out of the wagon at the back door of the lodge, their future guide was half sprawling, half sitting on the porch step. He didn’t change his position until Uncle Andrew invited him inside and introduced his guests from New York.
    Even then, Slim stood looking down, one toe scraping the living room floor. He didn’t offer to shake hands till the boys offered theirs. He didn’t even look in the direction of the girls until Trixie stepped up to him and announced, “I’m Trixie, Brian and Mart’s sister, and this is Honey Wheeler.”
    “Evenin’, miss,” Slim drawled.
    He came to life, though, when the Bob-Whites spread their purchases around on the living room floor. The carbide lamps seemed to intrigue him. He picked one up, fooled with it a minute, then put it down. His eyes narrowed at the accumulation of candles, waterproof plastic cases, pickax, shining nylon ropes, and hard helmets.
    “What do you aim to do with all this truck?” he asked.
    “It’s all gear that has been recommended by the National Speleological Society for cave explorers,” Uncle Andrew explained.
    Slim snorted, passed a worn, frayed rope between his hands, then picked up his lantern. “These are all anyone needs,” he said. “See you in the mornin’. I’d figured to get goin’ this afternoon, but it’s too late now. Is eight o’clock too early for you dudes?”
    Trixie bristled. “All of us dudes are strong enough and healthy enough to start out right now. We’re ready if you are.”
    “See you at eight o’clock tomorrow mornin’,” Slim repeated and ambled toward the back door. “An’ go slow on packin’ all that dude stuff along with you. I don’t want to have to carry one of the womenfolk.” Trixie was speechless—that is, till she closed the door after Slim. Then she exploded.
    “Do we have to go exploring with that—that—”
    “Now, now, Trixie,” Uncle Andrew said. “Slim’s probably all right. He’s just like any other young fellow around here would likely be—not afraid to grapple a wildcat with his bare hands and thinking all official equipment is sissy. Hold your ammunition for a while.”
     
    “I think first impressions are best,” Trixie said confidentially to Honey when they went upstairs to get ready for dinner. “I’ve hardly ever been wrong on first impressions, and there’s something sneaky and odd about that Slim.”
    “Oh, Trixie, I don’t think so. If you think back, you’ll remember several times when you've both suspected people and were wrong about them.”
    “Name just