God keep you and save you, my dear sister, and my affections to JeannPhillipe and little Bastien, Anette, and Joséph — he must be quite the pup now! Surely Jean-Baptiste must by now have returned to France and is making a recovery from his bloody flux; convey my warmest brotherly affections. Beyond São José Tarumás there will be few, if any, opportunities for communication, so this may be the last letter you receive from me until I complete my experiment. If you should see Marie-Jeanne, the simple imparting of these words would give her comfort and certainty while we are necessarily parted: My mind is made up, I am decided: yes, I shall, yes. With all my heart.

With loving affection

Your brother

Robert.

Luis Quinn made his first exercise at dawn. The Fé em Deus lay anchored to a cable from the northern bank, a guard against escape though the slaves slept chained to their oars. Rags of mist coiled across the water and clung to the trees that crowded down to the cracked, muddy strand. The river was an ocean, its farther bank invisible through the vapors stirred from its deep-secreted heat. Sound hung close to the surface, pressed low by the layers of warm and cool air; it seemed to come from all sides at once, from immense distances. Luis Quinn found himself holding his breath, holding every creak of joint and pulse of blood still to unpick the weave of voices channeled along the river. The pagan roar of howler monkeys — they no longer terrified him as they had that second night out from Belém when they seemed the infernal host of Babylon — the frogs, the insects, the whoop and scrape of the morning birds, but beyond them … splashing? Oars? He strained to hear, but an eddy in the flow of heat and cool swept the faint noise back into the general chorus. Suddenly all other senses were overwhelmed by the smell of deep water, cool and sacred. A joy so intense it was pain made Luis Quinn reach for the rail. He could feel the river run, the world turn beneath him. He was infinitesimal, embedded in glory and unknowing, like a nut in its thick casing on the branch of a great tree. Quinn turned his face to the pearl-gray hidden sun; then pressed his hand to his heart. Sin to worship the creation before the creator. And yet … He set his leatherbound book on the rail, undid its lacing, opened the handwritten pages. A joy, a fire of another kind, his painstaking translation of the Spiritual Exercises into Irish. The Second Week. Fourth Day. A Meditation on the Two Standards. Loyola, that subtle soldier: the untranslatable pun.

“A glorious morning indeed, Father.”

The violent loudness of the voice as Quinn prepared to descend into quiet was like a blow. He lurched against the creaking, unsound rail.

“Forgive me, Father, I did not mean to alarm you.”

Falcon stood at the aft of the ship half-shadowed by the awning. He too balanced an open book on the rail, a soft suede-bound sketchbook in which he drew with charcoal.

“Our superior general prescribes dawn as the best time for meditation.”

“Your superior general is right. What is today’s subject?”

“The Two Standards, of Christ and of Lucifer.” At many junctions and embarkations in his life Luis Quinn had returned to the disciplines of the Spiritual Exercises. The packet from Coimbra to Lisbon had been brusque business, he no more than freight. The calm-bound crossing to Salvador was for prepararion, for the lingua geral and the writings of the great explorers and missionaries. The slow crawl up the coast to Belém do Pará had been the opporrunity to study his follow traveler and subject — this small, fierce man of strangely juxtaposed convictions and doubts and swift, ill-concealed humors. But the river, that province of time as much as distance, unchanging and never the same from breath to breath, was the true embarkation to the celebration of discipline. “We are commanded to envision a vast plain about Jerusalem, and mustered upon it around his banner the armies of our Lord; and in the same work of the mind’s eye that other vast plain around Babylon, where around the banner of the deceiver are gathered the forces of Lucifer.”

“How do you imagine it, the standard of Lucifer?” Fé em Deus was waking; the movements of the crew sending luxurious ripples across the glassy water.

“Golden of course, like a bird, a proud bird of prey with feathers of flame and diamonds for eyes. He was a Lord of Light, Lucifer. Quite quite beautiful and so skillfully made that the diamond eye enchants and seduces everyone who sees it so they think, Yes, yes, I see myself reflected there and I am good. Excellently good. Who would be drawn to it if it did not mirror their vanities and answer their hopes?”

Falcon gave his whole weight to the rail and looked out into the morning, where bands of blue were appearing as the higher mists evaporated. “You have a great gift for visualization, Father. I find that I must augment my memory with material aids.” Quinn glanced at the doctor’s book. The double-page was covered in a drawing of the visible shore, the line of the trees, the taller tops rising above the general canopy, the jumble of high birds’ nests, the zones of the strand: the scrub vegetation — a writhe of black denoted the jacaré in the lee of the bleached fallen branch — the edge-grasses and the cracking reach of the exposed muds and silts. Captain Acunha never tired of saying he had never seen the river so low. The whole was annotated with comments and footnotes in a strange cursive.

“I have no hand for the drawing,” Luis Quinn said. “Your writing is unfamiliar to me. Might I ask what language?”

“A code of my own devising,” Falcon said. “It’s not unknown for scientists to need to keep their notes and observations secure. Ours is a jealous profession.”

“Some might see it as the work of a spy.”

“Would a spy show you that he writes in code? Look! Oh look!” Quinn’s attention darted to where the doctor pointed, leaning intently over the rail. Yes , he had been about to say, if that spy thought that those notebooks would be found later, by stealth or theft.

A mound in the water, a wheezing spray of mist broke the surface and vanished into spreading ripples. A moment later a second apparition surfaced and submerged in a soft rain of exhalation. The two circles of ripples met and clashed, reinforcing, canceling each other out. Falcon dashed, flapping coattails and loosely bound sheaves of paper, along the narrow gunwale to the bowsprit, where he clung, keenly scanning the misty water through his peculiar spectacles. “There! There!” The two humps arced through the water as one a short distance ahead of the ship, blowing out their lungs in a gasp of stale air. “How marvelous, did you see, Quinn, did you see? The beak, a proonounced narrow protrusion, almost a narwhal spear.” He dashed excitedly with his coals on the paper, never taking his eyes off the close, hazed horizon. “The boto — the Amazonian river dolphin. I have read… Did you see the color? Pink, quite pink. The boto: extraordinary and I think unclassified. To catch one, that would be an achievement indeed: to have the classification Cetacea Odontoceti falconensis. I wonder if the captain, the crew, even my own staff might obtain one for taxonomic purposes? My own cetacean…”

But Luis Quinn stared still into the pearl opacity that hung across the river. A plane of shadow, a geometry, moving out in the mist upstream of Fé em Deus , glimpsed and then lost again. There. There! His flesh shivered in superstitious dread as the dark mass resolved in the mist, like a door opening onto night, and behind it, another rectangle of lesser grayness. What uncanny river-phantasm was this? Silent, uterly silent, without a ripple, floating over water not on it. Luis Quinn opened his mouth to cry out in the same instant the lookout yelled a warning. Captain Acunha on the stern deck whipped glass to eye. Quinn saw his unmagnified eye widen.