Lunar Caustic

Dear Readers, I am very pleased to retrunk “Lunar Caustic” today. As you may recall, this is the story that won the 2026 “Goobie” Award for Speculative Fiction,¹ which after years of hard work finally launched my career into the stratosphere (movies, merch, etc.), at least for a season or two, until … well, never mind. Enjoy! —JS-R, Vacaville Resettlement Camp, Occupied California, September 2029

Lunar Caustic

Dear Readers,

I am happy, if somewhat nervous, to present to you today a guest piece from my dear old friend Nénuphar de Q****.

Nénuphar and I go way back, and I could not even begin to summarize for you all the different projects we’ve collaborated on over the years. She has asked me not to bother with a summary of her several advanced degrees, her long list of honorary doctorates, her prizes, her damehoods, or her numerous other accomplishments, and doesn’t even want me to specify her current institutional affiliation. (She does not mind my telling you however that she is the 2021 winner of the GLAAD award for outstanding representation of the lesbian, gay, bisexual, and transgender community in scientific research.) So I’ll just say that I sincerely think Nénuphar has one of the most original and wide-ranging minds of anyone I’ve ever known.

My trepidation, however, is not unconnected to her insistence that I make no mention of her affiliations. For while I have not looked closely into the matter (it’s the rentrée scolaire right now, and I’m very busy with administrative meetings and with putting the final touches on my syllabi), I gather that the information I am permitting her to divulge here has been, up until this very moment, a carefully guarded secret among her close collaborators, and that her decision to make it public has caused a significant rupture in the research community, which may threaten her standing within it, and eventually even her livelihood. Nénuphar has insisted to me, however, that the public interest in this matter trumps whatever protocols one should ordinarily hold to, and that she is prepared to face whatever consequences come her way.

As she wrote to me just this morning —and I really don’t have time right now to verify or even to absorb fully what my dear old friend is getting at—: “If you had seen photographic images of actual events that took place almost half a billion years ago, would you really be able to keep them hidden from the world just because your colleagues were dithering and squabbling over who gets to be first author on the preprint?”

What can I possibly add to this? C’est ton affaire, chère Nénuphar, et je te fais entièrement confiance. Je ne suis là que pour te fournir une plateforme.

—JS-R
Les Buttes-Chaumont, September 2023

Lunar Caustic

There are several milestones in the early history of photography, but common convention extends its honor for “the earliest photograph” to one Nicéphore Niépce, of Chalon-sur-Saône, in 1826. His Point de vue du Gras [View from the Window at Le Gras], a heliograph made by spreading bitumen of Judea over a pewter plate and exposing it to direct sunlight, hardly retains much today in the way of a recognizable image:

But, when colorized and enhanced, we can indeed still make out the distinct contours of some old French farm buildings, and beyond them an unmistakable scene of the countryside at Saint-Loup-de-Varennes:

The honor of primacy goes to Niépce mostly in view of the permanence of the image he created. But among historians of photography other precedents are generally given at least brief acknowledgment as well. By the early eighteenth century, in fact, several experimenters in different European countries had converged on the idea that elemental silver, combined with some other metal, mineral, acid, or salt, is unusually receptive of the objects that lie exposed to it in ambient light. As early as 1717 the German chemist Johann Heinrich Schulze, much by chance noticed the light-sensitive properties of argentic salt, which he described two years later in a treatise entitled Scotophorus pro phosphoro inventus, seu experimentum curiosum de effectu radiorum solarium.

It is impossible to render the first part of this title in elegant English, but the core idea is that the author, having conducted a curious experiment on the effects of solar rays, discovered a new substance that he called the “scotophor”, a sort of complimentary element to phosphorus, discovered for its part by Hennig Brand in 1669. Rather than “conveying light”, as the name of Brand’s new element suggests, the scotophor instead is a “conveyor of darkness”. That is, with an appropriately positioned sheet doused in a slurry of chalk and silver nitrate —or “lunar caustic”, as the alchemists once called it—, the dark objects directly before the sheet will be conveyed to it and leave a trace of themselves.

This lunar caustic, or, if you prefer, this silver nitrate —or again, if you do not wish to take sides in the chemical theater of the querelle des anciens et modernes, this AgNO₃— had been artificially produced since at least the thirteenth century, notably by Albertus Magnus, by adding nitric acid to silver, which had the well-known virtue of dissolving silver and facilitating its separation from gold. But the general scholarly consensus is that no one prior to Schulze had noticed the second great use of silver nitrate, whose innovation would launch the era of the photographic image.

It is thus in itself a significant discovery of the research group I have been involved in for the past five years, that at least a few long-forgotten Spanish authors already discerned the “scotophorous” virtue of silver nitrate before the end of the sixteenth century. All of these authors had been active in the Viceroyalty of Peru, established in 1542, and seem to have witnessed firsthand the excavations at the silver mines of Potosí. The nearby mountain known as Cerro Rico was to become, by the end of that century, the source of well over half of the global silver trade, which profoundly transformed the modern world economy. With the constant traffic of galleons between Acapulco and Manila, soon enough over thirty percent of Potosí’s silver was to end up in the reserves of the Yuan Dynasty in China, a mass-scale interhemispheric transfer of wealth whose consequences are still being felt today.

This part of the story is familiar enough. What has been entirely overlooked, at least for the past several centuries, are the curious phenomena that were observed and described by our newly rediscovered Spanish colonial authors under the name of “moon mirrors”. According to Juan Gonzalo de la Cueva, author of the short treatise El Espejo de la Luna (Madrid, 1584; Latin translation Speculum Lunae, Paris, 1603), these are the same as what were in local Quechua lore known as “moon prints” — what appear to be images of the moon, sometimes surrounded by small dots in roughly the same positions as the stars of the equatorial sky, that are seared at various locations into the surface of Cerro Rico. Indigenous Andeans are reported to have believed that the moon itself occasionally descended to the surface of the earth at night and “sat” for a while on the slopes of the mountain, leaving behind a print much as a foot would. But de la Cueva could not avoid noticing the incongruity of size, which would of course, he insisted, rule this foolish superstition out. But neither, he noticed, could these impressions be explained by appeal to any known human art, in view, he wrote, of their “nearly perfect likeness to the moon itself” [su similidad casi perfecta con la Luna misma].

Now, Albertus and others believed that lunar caustic must be manufactured in the alchemical workshop, as one of its key ingredients, nitric acid, is not naturally occurring. But we know today that severe thunderstorms, with repeated cloud-to-ground currents, occasionally bring about temperatures high enough to produce nitrogen dioxide, which in combination with water forms nitric acid. In principle, then, wherever we find both exposed elemental silver and frequent lightning, we might expect to discover at least some naturally occurring lunar caustic. And where we find this, in turn, we might also expect to discover, as de la Cueva seems to have done, naturally occurring photographs.

I am ready of course to acknowledge that I am no Hispanicist, let alone an Andeanist, and that the rediscovery of the Bolivian moon mirrors must be entirely credited to the work of my by now undoubtedly former colleagues. I am however, among many other things, a chemical stratigrapher and a paleoclimatologist, and even, briefly, a former mining engineer — and once I had seen for myself that silver nitrate may be naturally synthesized, I immediately understood the importance of going and looking for other locations in the world where conditions may be, or may once have been, similar to those at Cerro Rico. And if those conditions are no longer apparent at the surface of the earth, I understood, then we will have to dig down into the earth to find them.

This was the occasion of the first cleavage in our interdisciplinary group, as it is the moment when we lost Pablo, Eleuthera, and Lauren, who would have preferred to stay on what was, for them, the familiar terrain of South America.

Rainer, Gildo, and Fuyuko were still with me, however, and together we quickly compiled a database of sites around the world that may have had both exposed silver deposits and significant lightning activity in the past. We identified two ideal spots. The first site lay near the Iremel ridge in the southern part of the Ural mountain range in the Russian republic of Bashkortostan, where the data indicate ideal conditions prevailing in the early Eocene, roughly 50 million years ago. The second site we identified lay in the Harz Mountains in Lower Saxony, where paleoclimatological and stratigraphic data indicate significant lightning strikes meeting exposed silver in the period of the middle Permian, almost 400 mya. We knew right away, in view of NATO’s aggressive eastward expansion and Russia’s justified self-defense, that there could be no possibility for us of conducting field-research in Bashkortostan in the near future.² And so the most promising pathway open to us lay in northern Germany, in the silver mines that had filled the coffers of the Hannoverian court since the seventeenth century, and whose shafts the great G. W. Leibniz had once explored, in the hopes, I’ve been told, of figuring out a way to flush the silver deposits out by the use of hydraulic pumps.

So we set off, the four of us, for Germany, Rainer and Gildo’s own Vaterland, where we took up residence at an inn called “Zum Roten Kreuz” in the Saxon town of Seesen. The boys took a room together, and when Fuyuko and I went to pick them up for dinner we found them already eagerly fondling their chisels and drills, in anticipation of the subterranean excursion we were to make at dawn. My own roomie, never much of a talker, seemed unusually quiet, as if overtaken by a foreboding she herself could not yet understand or express.

Thanks to some precious contacts in the Niedersächsisches Landverwaltungsamt [the Lower Saxony Office of Land Management], my team and I gained easy access to the site of a condemned mine, which had been opened in the era of Leibniz, and closed already by the 1740s. Upon entry, just meters below the surface, we discovered some ominous graffiti that appeared, on first inspection, to date from the era of the shaft’s first usage. Umkehren! it warned us. Turn around! But this message was surrounded by various obscene images of what appeared to be vulvae —unfortunately not the Paleolithic kind, which, if that had been the case, I probably would have dropped everything to study, but only the kind that might have fired the imaginations of early-modern miners—, so we took the warning with good humor and we kept going.

Before noon we had already descended to a depth with significant Permian outcroppings. We chiseled off as many samples as we could carry, and by evening had returned them to our makeshift lab at “Zum Roten Kreuz”. What we found, at a magnification of 7.647 pixels/μm, will likely not surprise anyone familiar with the microstructure of silver:

You can of course indulge your imagination with an image such as this, pretending for example to see a rough map of Europe off to the upper left side, with the Mediterranean and Africa below, even a little boot of Italy and a placid Aegean Sea alongside it, as well as some inexplicable black abyss separating Asia off to the upper right (the Urals?). Perhaps those same obscene-minded miners indulged themselves with such games, imagining that they saw spread-legged Mädels in the curves and cracks of the stony shaft. It was said of old that the power of a witch lies precisely in the strength of the imagination, by which such impotent projections as the miners made are able truly to bring about in a solid external body the shape, indeed perhaps even the being, of the thing imagined. But we know better.

And yet, I had a sort of instinct that told me to push further. So we increased the magnification, to 16.785 pixels per nanometer, and what we saw left us all speechless:

Against everything we had learned from our first introductory chemistry courses on, it appeared as if this more intense magnification, rather than showing us more elementary structures, had quickly brought us to a level where reality itself smoothed out, into a fairly simple, though also somehow spotty, planar surface, or what Aristotle would have called a “homeomery”. Gildo interpreted this as a simple artifact of measurement, while Rainer insisted that our equipment was simply malfunctioning at such a high degree of resolution.

It was already late, but we determined, rather than to continue increasing the magnification, to exhaustively inspect all of the chiseled samples we had brought back at the initial resolution of 7.647 pixels/μm. There were hundreds of them, and it took us all night, but we found nothing at all, other than structures similar to the ones we had first discovered with our distorted little black-and-white map of Europe.

We went back to our room and fell asleep at dawn — the exquisite German Morgendämmerung! When I awoke I found Fuyuko next to me, still asleep, like a frail fallen angel. The boys, I soon learned from the cleaning lady, had set out in the direction of the mines over an hour ago. I was furious with them, of course, but also inwardly happy for the extra time it afforded me to continue exploring, with Fuyuko, whatever we might find at different levels of magnification. If that’s what Rainer and Gildo wanted, then fine, let us indeed pair off. They’re not going to find anything new down there, I told Fuyuko excitedly as I shook her awake.

We got our coffee (it’s always a pain to get them to let you bring it up to your room in this part of the world), and we returned to the same sample that had shown us that mysterious smooth surface the day before.
“What if,” I asked her, “we were to push the magnification as far as our instruments allow us?”
“You’re talking about roughly 4 picometers per pixel there,” Fuyuko replied in her usual soft monotone. “That’s not exactly Planck’s constant, but you’re at a level where you’re not likely to see much more in the way of interpretable structure, especially given that what we already saw yesterday at a vastly more zoomed-out level was basically no more structured than porridge.”

I told her to wait a sec while I texted the boys to see where they were at, and was not terribly surprised to find my phone stuck in “sending” mode, only to tell me after a minute or so that the text had failed to transmit. “They must be deep in the earth right now,” I said, and then I saw that Fuyuko had already prepared the sample and brought it up on the screen. When I looked at the screen I could not believe my eyes:

It was as if, somehow, structure had reappeared again, beneath the homeomery. This in itself was of course strange enough. But the real wonder lay, as you, reader, have surely noticed, in the unmistakable resemblance of the geometrical patterns we were now seeing to the iconic 1826 photograph by Nicéphore Niépce with which we began this unusual guest contribution to my friend’s Substack, which by now, I hope you will agree, has already taken you through at least a few unexpected twists and turns.

“What the fuck,” said Fuyuko flatly.

O, I thought, what strange argentine folds of our earthly passage! O silver! You were always runner-up, always married to the moon rather than to the sun, always second to gold in the hierarchy of human greed. But just look, now, at the record you have kept for us, at this subterranean archive and treasury… of what exactly? What are we seeing here, now?

We both agreed to proceed as our calm and sober scientific method dictates, and to go on making observations that might rule out instrument error. I asked Fuyuko to prepare another sample, and no sooner had she started than there was a knock at the door. It was the proprietor of “Zum Roten Kreuz”, who had come to deliver to us the worrisome news of a collapse at the mine. It’s in a fairly remote area, he said, and the last time this happened, when some kids got stuck down there back in ‘86, it took the Rettungsdient [Rescue Services] over three hours to arrive on the scene. He promised to keep us updated on any further news of our missing colleagues. I shut the door and turned to Fuyuko, who had been standing straight, but quickly dropped down behind her laptop’s screen — though not before allowing me to catch the tail-end of a fleeting smile on her face. (Fuyuko, mind you, does not smile more than once in a blue moon.)

I could not tell whether it was a nervous or a contented smile, nor whether it had to do with the fate of Gildo and Rainer, or rather with what she had just pulled up on her screen. But I could not ponder that ambiguity further, for no sooner had she sat back down than she said: “You’ve got to see this. Here’s a sample at 8 picometers.” And she pointed her brittle finger at the screen, and this is what I saw:

“But look what happens,” she continued,” when we bring it back down to 4.” And there, on the screen, I immediately recognized the unmistakable image of Niépce’s second most famous work, also of 1826, La table servie:

I was trembling, and I begged Fuyuko to stop, but it was as if she could not hear me. She prepared another sample and set the magnification at 8 picometers again, and this is what we saw:

And then she moved it again to 4 picometers, as tears began to stream down my cheeks. And this is what we saw:

And then another, at the same resolution:

And then another:

At the border of hysteria, I screamed at her to stop. She relented, and we both sat for a while — I sobbing, Fuyuko in perfect silence. After a time we both stood up again, as if synchronized.

I looked at Fuyuko. She looked at me. We were seeing the same things, but she was also seeing something I could not see. I was as if entirely beholden to her, and I felt somehow that this was the moment of our own secret chymische Hochzeit,³ uniting us in some eternal mystery. She walked across the room and looked out the window at the farmhouses that lay in the distance, beyond our little town of Seesen. It was dusk and the sky was red — it was the Abendrot, just as the great Eichendorff must have seen it.⁴ We were silent for what must have been a minute or so, and then Fuyuko muttered, without turning around: “We’ve been through all this before.”

I shivered for my poor Fuyuko, who alone, it seemed to me, was able to comprehend in an instant everything this was to signify for us.
“Soon it will be time to sleep,” I said incongruously.
“If only not to go on erring in our solitude,” Fuyuko replied. These words chilled me to the very marrow of my spine, though I swear to you I still don’t know what they mean.

—N. de Q***
Quimper, Bretagne

1. As Ted Chiang, president of that year’s prize committee, declared at the ceremony: “‘The Lunar Caustic’ [sic] fundamentally transforms our idea of what is possible in speculative fiction.”

2. I’ve only been able so far to skim over Nénuphar’s essay, but in doing so my eyes just happened to land on this particular sentence. I have always strongly disagreed with my friend on political matters, and I cannot stress enough how completely she and I disagree about the causes of the war in Ukraine. But friendship is friendship, and if I am going to give my dear Nénuphar a platform here at The Hinternet, I may as well let her come across to my readers as she really is, in all her complicated —and compromised— glory. —JS-R.

3. Just a quick clarification here: Nénuphar is referring, evidently, to The Chymical Wedding of Christian Rosenkreutz (also known as “Christian Rosy-Cross”), a book published in Strasbourg in 1616 and generally attributed to the German theologian and natural-philosopher Johann Valentinus Andreae. This work played an important role in increasing the popularity of the Rosicrucian movement in Protestant Europe, and offers a vivid illustration of the allegorical deployment of such irreducibly social notions as “marriage” within the context of scientific research into the properties of the chemical elements. —JS-R

4. I happened also to notice this reference in my rapid skim of the text, and I just wanted to jump in and say that it is in particular in the segment of the linked recording extending from 5:14 to 5:38 that Jessye Norman, via Richard Strauss, via Joseph von Eichendorff, draws out for us the full force of the mood that must have been hanging over our Nénuphar at the moment she is seeking to capture. —JS-R