Chickenhawk Dunn leaned back in the rocker and set his heels up on the porch railing. He had a book spread on his lap, and on its pages danced geometric depictions of planetary motions. He struggled with the Latin, but the embedded calculus alone described beautifully the orbits' ellipses and triangulations. Between pages his eyes glanced up, past the porch railing, over the lake, and to the auburn mountains beyond. The thunderhead, stopped short by Trout Peak & company, had rolled away north some twenty minutes ago, off to bother the Montana territory. Twenty minutes of quiet, with no sight nor sound of his little sister Jackalope.

Sighing, he loosened the top button of his waistcoat; though historically a slender-framed boy, he had somehow enlarged over the winter. Between his eighteenth and nineteenth birthdays he had spurted to a height of six feet two inches, and in the subsequent months had put on perhaps fifteen pounds in his shoulders and chest. Ma had been overjoyed, but Chick's physical comfort had suffered for it.

He flattened the book, and over its pages he packed his pipe, using the book's spine to catch the dropped bits of tobacco. Of late his fingers had thickened and become clumsy.

"Doggone it," he whispered, collecting the stray leaves in his palm and thumbing them into the narrow pipe bowl. He thought of Jack performing a similar stunt with a jovinium marble in free-fall, and again his eyes searched the eastern mountains. He fumbled for a match.

"Chickenhawk," said Ma, and the boy jumped in his seat. The whole porch creaked from the impact. Ma left the doorstep and walked around to Chick's side where he could see her. "Sorry," she said. Over the front of her flannel shirt hung an egg-stained apron. "Ain't heard yet from Jackalope?"

Chickenhawk sighed and pulled a match. "Nope," he said. He made a light and puffed the makings to a glowing cinder. "I reckon she'll be along shortly."

"I reckon so," said Ma. She tugged at her suspenders. "Might be worth saddling Oscar and scouting up by Trout. She might have burned through her crystal and made landing on the peak."

Chickenhawk peered into his pipe bowl, tampering the cinder with the back of a pencil. "You mean for me to go?"

Ma folded her arms. "I could do it, if you're busy."

"I ain't busy. It's just that she's been late before. I can count on my thumb the number of times she's been early."

"The storm passed twenty minutes ago."

"That seems a high figure," said Chick. "I reckon it ain't been more than fifteen. Besides: if she dropped out the cloud as it was moving off, she'd have likely been on the eastern side, and at a low altitude. Not being able to fly back in a straight trajectory through the mountain, she'd be left with no choice but to circumnavigate it." With his pencil he doodled something in the book's margin. "Yup, it'd take roundabout fourteen minutes if she hopes to conserve her crystal. I reckon she'll be along shortly."

Ma snorted. "You're being ignorant, Chickenhawk."

"No I ain't."

"If that girl come down off the eastern slope like you say, she'd have hit that updraft with a parabolic dive and got lift enough to clear the peak with naught but a tap or two of throttle. What force you reckon could drag her to a low altitude with no top pressure and a gale at her back?"

"Humidity," said Chick.

Ma blinked. "We fixed that. Y'all tested it."

"Tested at standard pressure, in stilled air that's dry as toast." Chick shook his head, drawing on his pipe. "We ain't got no wind tunnel in that barn. We ain't got no steamer. I chalked it out on the board and you seen my figures. But there ain't no substitute for experiment."

Ma's red eyebrows furrowed. "You saying she might have stalled?"

Chick glared at her. "I ain't saying that. I'm saying the wetness might drag the turbine some." He turned back to his book. "You're the one implying she's been struck by calamity."

"If the thunderhead was pounding the peak while she tried to clear it, calamity's what she would have found."

Chickenhawk chewed the pipe stem. "I don't reckon she'd be able to climb that high."

"I guess," said Ma. She glanced over his shoulder. "Is that the Principia?"

"Yup."

"In Latin?"

"I wanted to hear the man's own words."

A yellow flash on the horizon drew their eyes. They watched and listened. But there was only the lapping of the lake and the wind in the pines.

"I'll give her another minute," said Chick. "Then I'll saddle up Oscar."

"Could you use some company?"

"I reckon so."

"I'll get my boots," Ma said, turning for the door. "We really ought to build a second engine."

"You said you couldn't jockey no more."

"I could if I had to."

Then from the east came a whirring, what built up quiet but quick, like a gnat flying into one's ear. Ma whipped around, clutching the door frame. Chickenhawk leaned forward, his feet dropping to the porch boards.

The whirring grew, and then there glowing over the treetops was the orange ball of light, looking like a will-o'-the-wisp as it brightened and swayed in its direct approach. Chick snapped shut his book and stood. "That'll be the experiment right there, in flesh and blood."

"Sure as thunder from a storm," said Ma.

Jackalope cut her throttle and swooped low over the house and made a wide pass around the ranch, limbs extended, dropping speed.

Ma shook her head. "She ain't lined up with the launch."

"Give her a minute; she's got to slow down first."

"She's too danged light. I told her she can't be punching the throttle when she ain't got the mass to warrant it. If you can't stop, you oughtn't get going in the first place."

This tale has been unlawfully lifted from Royal Road; report any instances of this story if found elsewhere.

Jackalope dropped to twenty feet and as she approached the near end of the launch she spun round and throttled opposite to her trajectory to cut speed. She lowered her feet, bent her knees, threw out her arms, and looked back over her shoulder to keep the shimmering wooden path in sight.

"You didn't cut it when you should," whispered Ma.

Jack maneuvered the waxed soles of her boots to keep them parallel with the pine boards but in the last moment her right arm wavered in the crosswind and she tilted so that her right boot made contact before the left. She was spun by the impact and slapped her hands on the wood to keep from losing balance, but the brass engine on her back was too heavy so after skating on all fours for just a few feet she collapsed to her side and slid like a dog on ice down the rest of the launch and tumbled off the far edge into the grass.

"Dang it, Jack!" hollered her brother. He vaulted the porch railing and ran to her with long strides.

The girl tried to stand but her trembling knees buckled and the weight of the engine toppled her to her side. "Aw, heck," she said, and punched the dirt.

"You just hold on a minute," called Ma from the porch. "Let Chickenhawk liberate you."

"I don't need no goldarned liberating!" hollered Jack. She went to wrestling with her strap buckles.

Chick was upon her now. He swatted away her hands before unlatching her waist belt, followed by each of her shoulder straps. The engine dropped from her back and relaxed into the grass. Jackalope sat up and with shaky hands tried to loosen her thigh straps what had ridden up tight in her groin from the impact.

"You let me get those," said Chick.

"I got em."

"You're windwhipped, you goof! Can you even bend your fingers?"

"I could bend you, you varmint." With a grunt she unlatched one of the buckles and it sprung off her and clanged against the engine. "Ha!" she cackled.

Chickenhawk stood and fixed his necktie. "Are you broke anywhere?"

Jack didn't answer. She was fighting the other thigh strap, her lips curled up in a snarl.

"Alright then," said Chick, and he walked back to the porch.

Ma was standing on the top step, tugging at her suspenders. As Chick approached she said, "Anything broke on her?"

"If there is she don't sense it."

"And the vest?"

Chick passed her and collapsed into the rocker with a sigh. "The chassis is scuffed as usual, but the engine looks fine." He picked up his pipe and went to re-lighting it. "And them straps are doing their job."

A second clang rang out, and Jackalope hoisted herself to her feet. She wobbled in a circle like a drunkard, then froze, arms out, shaking her head, blinking in the wind.

"Is she concussed," said Ma, "or just windwhipped?"

"The latter," said Chickenhawk. He opened his book and flipped back to his place. "The rest of it I chalk up to poor breeding."

"You hush."

Jackalope approached the porch in an irregular trajectory, fighting the wind as it plucked at the canvas between her limbs, slapping and tripping her. Upon reaching the bottom step she did not attempt to mount it but rather clasped a shaky hand on the railing and squinted up at Ma. Her dark skin was flushed with exertion, turning her mahogany. "Is breakfast on?" she said.

"It will be," said Ma, "once you haul that vest back to the barn."

"I'll get it later."

"Your arms don't look broke."

Jack spit in the grass. "Have Chick do it."

Her brother snorted a puff of smoke.

Ma leaned toward the girl and cocked her head. "You need to lie down?"

"Nope," said Jack. She removed her hood to reveal a shiny black dome of flattened hair; she proceeded to tear and pull it back to its upright tangled state of nature before violently shaking her head, throwing out a shower of frost and perspiration. Then her eyes crossed, and beginning to wobble she hugged the railing with both arms. "Have Bison do it."

"Bison's fetching the mail," said Ma. "And in any case, he's a guest here; he ain't no footman to be picking up after the likes of you."

Jack's bloodshot eyes narrowed, and in gasping for breath she bared her over-sized front teeth; these with their great gap between them, and in company with her flared nostrils, led her gaunt little face to resemble that of some irascible prairie-dwelling rodent.

They exchanged a long stare; when Ma did not budge, the girl stamped her foot. "Aw, heck!" She teetered herself around and shuffled uneasily back toward the launch.

"Girl," said Ma, "if you only landed as good as you back-talk you wouldn't be in this predicament."

Chick raised his eyes. "Be honest," he said to Ma at a volume too low to be overheard. "Her pa was a epileptic, wasn't he?"

"I told you to hush," said Ma. She moved to the door. "You help her if she needs it, or breakfast won't be on for you neither."

Chick watched her disappear into the darkness of the house. With his tongue he clicked the pipe stem between his teeth. He looked back at Jackalope: she was bending gracelessly over the engine, straining at it, her waxed boots slipping and kicking in the dewy grass. With a sigh Chick snapped shut the Principia and set it down in the rocker and went out to relieve his sister.

This time she gave him no argument. Gripping the leather straps in one hand, Chickenhawk hoisted the thirty pound contraption over his shoulder and lumbered ahead toward the barn. At first Jack just stood and watched him go, but then she seemed to change her mind and she trotted after him, folding her arms so her wings would not catch the wind.

In the barn chickens darted from the boy's steps as he shuffled across the hay-strewn floor and dropped the brass engine on the workbench, rattling tools and throwing up dust.

"Careful!" hollered Jackalope from the door.

With a rag Chick wiped his hands. "How much did you get?" he said.

"One marble."

"A whole one?"

Jack spat in the hay. "The goldarned crystal fractured in two. I marbleized both halves but then one escaped me."

Chick rubbed his neck. "Let me see her."

From the padded compartment in her terncoat Jackalope pulled the vial and held it out for him. With care he took it from her and held it up high in one of the many dusty sunbeams shining in through the ancient roof. The back-light penetrated the marble's shell and illuminated its shimmering purple core.

"She's got a good glint to her, and she's nearly spherical," he said. "Looks like you got the big half."

Jack sidled next to him and peered up to see what he was seeing. "I reckon so," she said. "This is the one caught my eye so that figures I guess." She frowned. "I could've got the rest of it but in the end I got yellow at the pace them mountains was advancing on me."

"Any jockey comes back alive from mining a thunderhead is a success." Chick turned the vial over and watched the marble's twinkling heart beat. "You done good, Jack. This here's plenty enough to get you back into the sky for another go."

Jackalope jumped up to sit on the workbench. "Ma will ask why I let her fracture."

Chick opened a cabinet on the wall and placed the vial into a bed of cotton amongst a half dozen glittering neighbors. "Tell her the humidity dragged on the turbine coming out of the cloud."

Jack furrowed her black eyebrows at him. "I did have some issue fighting the headwinds, but I didn't chalk it up to humidity."

"You ought to suggest that to her anyways, if she asks."

"That seems like a lie."

"It ain't a lie, exactly," said Chick. He rubbed his neck. "Ma was scared you weren't being quick enough to come back, so any questions is just to ensure you didn't make no silly mistakes. And you ought to oblige her that."

Jackalope snorted. "Well, I did forget to latch the hammer on the boltgun before my first shot; I figure that's what allowed the crystal time to fracture." She slapped the workbench. "But it was only thinking of Ma telling me not to do it what distracted me!"

"Don't tell her that."

Now there came a rustling through the grass and the siblings hushed up. Ma marched into the barn, with her queer bouncing steps and erect posture. She carried a plate of fried eggs, bacon, and toast; this she lay on the workbench next to the engine, and before the plate had settled Jackalope was leaned over it, snatching up little handfuls.

"Calm, you varmint!"

"Ma," said Chickenhawk, taking a piece of toast. "Jack mined herself a good sized marble. I reckon that gives us surplus enough to run our baseline."

Ma looked at Jackalope. "How big?"

Chick said, "About an ounce." He crunched his toast. "More than we had right to expect with them updrafts coming off of Trout."

Ma glanced at him, then looked back at Jackalope. "How'd the vest hold up against the air?"

Mouth full of bacon, Jack only shrugged. She stacked another four strips and an egg on a piece of toast and folded it and went to forcing the whole mess into her mouth.

"Dang it, Jack!"

Ma's eyes creased at the corners as she studied the display. "Look at that," she said. "Like a snake consuming a prairie dog."

"We ought to start tuning the engine now," said Chick. "If it goes south we'll need the day to repair."

Ma looked around. "We should wait for Bison. The mail must had to arrive by now."

Chickenhawk nodded, chewing, and proceeded spinning open the vice clamps mounted around the workbench. "I'll start setting her up; but we won't flip the switch until Cottonwood's back."