"Ye didna sense anything odd about yon stone when ye gave it to the lad, Sassenach?"

"No." I still felt shaken by the explosion, the echoes of that eerie noise still chiming in my inner ear. "It felt warm-but everything in the room is warm. And it certainly wasn't making that noise."

"Noise?" He looked at me queerly. "When it went bang, d'ye mean?"

Now it was my turn to look askance.

"No-before that. Didn't you hear it?" He shook his head, a small frown between his brows, and I glanced round at the others. Bree and Roger nodded-both of them looked pale and ill-but Ian shook his head, looking interested, but puzzled.

"I didna hear a thing," he said. "What did it sound like?"

Brianna opened her mouth to answer, but Jamie raised a hand to stop her.

"A moment, a nighean a nighean. Jem, a ruradh a ruradh-did ye hear a noise before the bang?"

Jemmy had settled down from his fright, but was still crouching in his mother's lap, thumb in his mouth. He looked at his grandfather out of wide blue eyes that had already begun to show a definite slant, and slowly nodded, not removing the thumb.

"And the stone Grannie gave ye-it was hot?"

Jemmy cast a glare of intense accusation in my direction and nodded again. I felt a small surge of guilt-followed by a much larger one, when I thought of what might have happened, had Bree not snatched him up at once.

We had picked most of the splinters out of the woodwork; they lay on the desk in a small heap of brittle fire. One had sliced a tiny flap of skin from my knuckle; I put it in my mouth, tasting silver blood.

"My God, those things are sharp as broken glass."

"They are are broken glass." Brianna clutched Jem a little closer. broken glass." Brianna clutched Jem a little closer.

"Glass? You mean it wasn't a real opal?" Roger raised his brows, leaning forward to pick up one of the needlelike shards.

"Sure it is-but opals are glass. Really hard volcanic glass. Gemstones are gemstones because they have a crystalline structure that makes them pretty; opals just have a really brittle structure, compared to most." The color was beginning to come back into Brianna's face, though she kept her arms wrapped tightly round her son.

"I knew you could break one if you hit with a hammer or something, but I never heard of one doing that that." She nodded at the pile of glimmering fragments.

Jamie picked a large shard out of the pile with finger and thumb and held it out to me.

"Put it in your hand, Sassenach. Does it feel warm to you?"

I accepted the jagged piece of stone gingerly. It was thin, nearly weightless, and translucent, sparkling with vivid blues and oranges.

"Yes," I said, tilting my palm cautiously to and fro. "Not remarkably hot-just about skin temperature."

"It felt cool to me," Jamie said. "Give it to Ian."

I transferred the bit of opal to Ian, who put it in the palm of his hand and stroked it cautiously with a fingertip, as though it were some small animal that might bite him if annoyed.

"It feels cool," he reported. "Like a bit of glass, like Cousin Brianna says."

A bit more experimentation established that the stone felt warm-though not strikingly so-to Brianna, Roger, and me-but not to Jamie or Ian. By this time, the wax had melted in the top of the big clock candle, allowing Jamie to extract the gemstones hidden there. He fished them out, rubbed the last of the hot wax off on his handkerchief, and laid them out in a row along the edge of the desk to cool.

Jemmy watched this with great interest, his misadventure apparently forgotten.

"D'ye like these, a ghille ruaidh a ghille ruaidh?" Jamie asked him, and he nodded eagerly, leaning out of his mother's lap, reaching toward the stones.

"Hot," he said, then, remembering, shrank back a little, a look of doubt crossing his small, blunt features. "Hot?"

"Well, I do hope not," his grandfather said. He took a deep breath and picked up the emerald, a crudely faceted stone the size of his thumbnail. "Put out your hand, a bhalaich a bhalaich."

Brianna looked as though she wanted to protest, but bit her lower lip, and encouraged Jemmy to do as his grandfather asked. He took the stone, still looking suspicious, but then the look of wariness faded into a smile as he looked down at the stone.

"Pretty rock!"

"Is it hot?" Brianna asked, poised to snatch it out of his hand.

"Yes, hot," he said, with satisfaction, holding it against his stomach.

"Let Mama see." With a little difficulty, Brianna succeeded in getting her fingers onto the rock, though Jemmy wouldn't surrender it. "It's warm," she said, looking up. "Like the piece of opal-but not way hot. If it gets way hot, you drop it fast fast, OK?" she said to Jemmy.

Roger had been watching this with fascination.

"He's got it, hasn't he?" he said softly. "Fifty/fifty, you said, or three chances in four, depending-but he's got it, doesn't he?"

"What?" Jamie glanced at Roger, then me, one red brow raised in question.

"I think he can ... travel," I said, feeling a tightening of my chest at the thought. "You know what Otter-Tooth said-" I nodded at the journal, which lay discarded on the desk. "He said they had to take a test-to see if they could hear 'the voice of time.' We know that not everyone can ... do this." I felt unaccountably shy, talking of it before Ian. "But some can. From what Otter-Tooth said, there was a way of finding out who could and couldn't, ahead of time, without having actually to try."

Jemmy was paying no attention to the grown-up conversation, instead rocking back and forth, humming to the stone clutched in his pudgy hand.

"Do you suppose the 'voice of time' is-Jem, can you hear hear the rock?" Roger leaned forward, taking hold of Jemmy's arm to compel his attention away from the emerald. "Jem, is the rock singing to you?" the rock?" Roger leaned forward, taking hold of Jemmy's arm to compel his attention away from the emerald. "Jem, is the rock singing to you?"

Jemmy looked up, surprised.

"No," he said uncertainly. Then, "Yes." He held the rock up to his ear, frowning, then thrust it at Roger. "You sing, Daddy!"

Roger accepted the emerald gingerly, smiling at Jemmy.

"I don't know any rock songs," he said, in his husky rasp of a voice. "Unless ye count the Beatles." He lifted the rock to his own ear, looking self-conscious. He listened intently, frowning, then lowered his hand, shaking his head.

"It's not-I can't-I couldna really say I hear hear anything. And yet-here, you try." He passed the stone to Brianna, and she in turn to me. Neither of us heard anything in particular, and yet I thought I could perceive something, if I listened very hard. Not exactly a sound, more a sense of very, very faint vibration. anything. And yet-here, you try." He passed the stone to Brianna, and she in turn to me. Neither of us heard anything in particular, and yet I thought I could perceive something, if I listened very hard. Not exactly a sound, more a sense of very, very faint vibration.

"What is it?" Ian asked. He had been following the proceedings with rapt interest. "Ye're no sdheanach sdheanach, the three of ye-but why is it you can do ... what ye do, and Uncle Jamie and I canna? Ye can't, can ye, Uncle Jamie?" he asked dubiously.

"No, thank God," his uncle replied.

"It's genetic, isn't it?" Brianna asked, looking up. "It has to be."

Jamie and Ian looked wary at the unfamiliar term.

"Genetic?" Ian asked. His feathery brows drew together in puzzlement.

"Why shouldn't it be?" I said. "Everything else is-blood type, eye color."

"But everyone has eyes and blood, Sassenach," Jamie objected. "Whatever color his eyes may be, everyone can see. This-" He waved at the small collection of stones.

I sighed with impatience.

"Yes, but there are other things that are genetic-everything, if you come right down to it! Look-" I turned to him and stuck out my tongue. Jamie blinked, and Brianna giggled at his expression.

Disregarding this, I pulled in my tongue and put it out again, this time with the edges rolled up into a cylinder.

"What about that?" I asked, popping it back in. "Can you do that?"

Jamie looked amused.

"Of course I can." He stuck out a rolled tongue and wiggled it, demonstrating, then pulled it back. "Everyone can do that, surely? Ian?"

"Oh, aye, of course." Ian obligingly demonstrated. "Anyone can."

"I can't," said Brianna. Jamie stared at her, taken aback.

"What d'ye mean ye can't?"

"Bleah." She stuck out a flat tongue and waggled it from side to side. "I can't."

"Of course ye can." Jamie frowned. "Here, it's simple, lass-anyone can do it!" He stuck out his own tongue again, rolling and unrolling it like a paternal anteater, anxiously encouraging its offspring toward an appetizing mass of insects. He glanced at Roger, brows lifted.

"You'd think so, wouldn't you?" Roger said ruefully. He stuck out his own tongue, flat. "Bleah."

"See?" I said triumphantly. "Some people can roll their tongues, and some simply can't. It can't be learned. You're born with it, or you're not."

Jamie looked from Bree to Roger and back, frowning, then turned to me.

"Allowing for the moment that ye may be right-why can the lass not do it, if you and I both can? Ye did assure me she's my daughter, aye?"

"She is most assuredly your daughter," I said. "As anyone with eyes in their head could tell you." He glanced at Brianna, taking in her lean height and mass of ruddy hair. She smiled at him, blue eyes creasing into triangles. He smiled back and turned to me, shrugging in good-natured capitulation.

"Well, I shall take your word for it, Sassenach, as an honorable woman. But the tongue, then?" He rolled his own again, in doubtful fashion, still not quite believing that anyone couldn't do it if they put their mind to it.

"Well, you do know where babies come from," I began. "The egg and the ..."

"I do," he said, with a noticeable edge to his voice. The tips of his ears turned slightly pink.

"I mean, it takes something from the mother and something from the father." I could feel my own cheeks pinken slightly, but carried on gamely. "Sometimes the father's influence is more visible than the mother's; sometimes the other way round-but both ... er ... influences are still there. We call them genes-the things babies get from their two parents that affect the child's appearance and abilities."

Jamie glanced at Jemmy, who was humming again, engaged in trying to balance one gemstone on top of another, the sunlight glinting off his coppery hair. Looking back, he caught Roger's eye, and quickly turned his attention to me.

"Aye, so?"

"Well, genes affect more than simply hair or eye-color. Now," I warmed to my lecture, "each person has two genes for every trait-one from the father, one from the mother. And when the . . er . . gametes are formed in the ovaries and testes-"

"Perhaps ye should tell me all about it later, Sassenach," Jamie interrupted, with a sidelong glance at Brianna. Evidently he didn't think the word "testes" suitable for his daughter's ears; his own were blazing.

"It's all right, Da. I know where babies come from," Bree assured him, grinning.

"Well, then," I said, taking back command of the conversation. "You have a pair of genes for each trait, one gene from your mother and one gene from your father-but when the time comes to pass these on to your own offspring, you can only pass one one of the pair. Because the child will get another gene from his other parent, you see?" I raised an eyebrow at Jamie and Roger, who nodded in unison, as though hypnotized. of the pair. Because the child will get another gene from his other parent, you see?" I raised an eyebrow at Jamie and Roger, who nodded in unison, as though hypnotized.

"Right. Well, then. Some genes are said to be dominant, and others recessive. If a person has a dominant gene, then that's the one that will be expressed-will be visible. They may have another gene that's recessive and so you don't see it-but it can still be passed to the offspring."

My collective audience looked wary.

"Surely you learned this in school, Roger?" Bree asked, amused.

"Well, I did," he muttered, "but I think perhaps I wasna paying proper attention at the time. After all, I wasn't expecting it actually to matter matter."

"Right," I said dryly. "Well, then. You and I, Jamie, evidently each have one of the dominant genes that allows us to roll our tongues. But But-" I continued, raising a finger, "we must also each have a recessive gene, that doesn't doesn't allow tongue-rolling. And evidently, each of us gave the recessive gene to Bree. Therefore, she can't roll her tongue. Likewise, Roger must have two copies of the non-rolling recessive gene, since if he had even one of the dominant genes, he could do it-and he can't. Q.E.D." I bowed. allow tongue-rolling. And evidently, each of us gave the recessive gene to Bree. Therefore, she can't roll her tongue. Likewise, Roger must have two copies of the non-rolling recessive gene, since if he had even one of the dominant genes, he could do it-and he can't. Q.E.D." I bowed.

"Wat's tes-tees?" inquired a small voice. Jemmy had abandoned his rocks and was looking up at me in profound interest.

"Er ..." I said. I glanced round the room in search of aid.

"That's Latin for your balls, lad," Roger said gravely, suppressing a grin.

Jemmy looked quite interested at that.

"I gots balls? W'ere I gots balls?"

"Er ..." said Roger, and glanced at Jamie.

"Mmphm," said Jamie, and looked at the ceiling.

"Well, ye do have a kilt on, Uncle Jamie," Ian said, grinning. Jamie gave his nephew a look of gross betrayal, but before he could move, Roger had leaned forward and cupped Jemmy gently between the legs.

"Just there, a bhalaich a bhalaich," he said.

Jemmy kneaded his crotch briefly, then looked at Roger, small strawberry brows knitted into a puzzled frown.

"Nots a ball. 'Sa willy!"

Jamie sighed deeply and got up. He jerked his head at Roger, then reached down and took Jemmy's hand.

"Aye, all right. Come outside with me and your Da, we'll show ye."

Bree's face was the exact shade of her hair, and her shoulders shook briefly. Roger, also suspiciously pink about the cheeks, had opened the door and stood aside for Jamie and Jem to go through.

I didn't think Jamie paused to think about it; seized by impulse, he turned to Jemmy, rolling up his tongue into a cylinder and sticking it out.

"Can you do that, a ruaidh a ruaidh?" he asked, pulling it back in again.

Brianna drew in her breath with a sound like a startled duck, and froze. Roger froze, too, his eyes resting on Jemmy as though the little boy were an explosive device, primed to go off like the opal.