C by Tom McCarthy

fuses from a metal cup and, after wiping its interior with her fingers, decants clear liquid into it from a bottle. A sharp smell burns Serge’s nose, inside the bridge. Wrinkling her own, Sophie sets the bottle down, sparks up the Bunsen burner and holds the cup over it. “What next?”
    “ ‘… over a gas flame till it—’ ”
    “I’m doing that already, stupid. Till it what?”
    “ ‘—catches fire,’ ” Serge reads.
    On cue, the cup starts burning. “Oh, wow!” says Sophie. The flames are blue, not orange; they make her eyes, already blue, glow bluer and her teeth flare bluey-white, like patterned marble.
    “We’re meant to pour it into a bucket of water,” Serge says, “but the room should be blacked out.”
    “Well, we’ll skip that,” Sophie tells him. “What’s next?”
    Next is an experiment with sulphur and dissolved nitre; then one with sulphates of potash and baryta; then another with nitrate of baryta and metal potassium. Serge reads directions from the Playbook; Sophie executes them, her face running red, orange, grey and blue again as each compound lights, flares or fizzles. When they come to heat up charcoal Sophie blows into the cup and they watch sparks fly out, the powder turning from black to red, then fiery white, before falling back grey and ashen, consumed by its own heat. As Sophie prods the ashes, Serge feels the reaction in his stomach again: a liquid flaring eating his own insides.
    “Pearl-ash next,” says Sophie. “Read out the next passage.”
    “ ‘If some more nitre be heated in a ladle, and charcoal added,’ ” Serge begins, “ ‘a brilliant deflagration (deflagro) occurs, and the charcoal, instead of passing—’ ”
    “It’s ‘day-flag-row,’ stupid, not ‘der-flower-grow,’  ” she says as she holds the new concoction over the Bunsen flame. “Carry on.”
    “ ‘—instead of passing away in the air … passing, passing away as …’ ”
    The queasiness is spreading to his head as his own stomach deflagrates, something sour and crimson blossoming, expanding. He looks up. Sophie’s staring at him, static. Her whole face seems to have slowed down—slowed down and expanded too. Her hair has expanded outwards from her head, rising to stand straight up in the air. His gaze follows it upwards and he sees instruments rise and hover above shelves. They do this incredibly slowly, as though willing themselves upwards, through excruciating effort, millimetre by millimetre. A window breaks, with the same slowness; he watches each of its glass fragments separate from the plane around it. There’s no crash or tinkle; there’s no sound at all. Serge tries to ask Sophie how she can make her hair stand up like that, but finds that his words, instead of travelling out into the air, push back into his mouth and on towards his stomach. Now sound and speed return, first as an after-rush of air, then, emerging from within this, a high-pitched hum that seems to have been going for some time but of which he’s only now become aware. Sophie’s still staring at him. Her hair’s tangled and her eyes are wild. A gasp comes from her mouth; then another, then a shriek of pleasure. She shouts something to him.
    “What?” he shouts back. The hum’s filling his ears.
    “Expl—” she begins—but he throws up right then, on the floor. His puke is red, laced with a briny, effervescent silver the same colour as potassium. Sophie looks at it, then back at him, then shrieks again, her shoulders shaking as the shrieks turn into sobbing laughs that judder her whole body.
    Their father opines later that there must have been some contaminant in the cup to cause such a violent explosion. He ventures, further, that Serge and Sophie’s extreme proximity to the point of detonation kept them from harm: had they been standing three feet from it, the force of the expanding air would have been enough to kill, or at least seriously injure, them. He plots diagrams