The Confusion

“Let me ask you this, Doctor: what is the exchange rate between Whig and Tory money?”

“Ah. At the moment, one of these-” he held up the Land Bank notes “-buys rather a lot of these.” He indicated the Bank of England notes. “For many are of the view that the Bank of England has failed already, and the Land Bank is ascendant.”

“Which amounts to saying that the Juncto will be cast down in the next election, and Harley will lead the Tories to victory.”

“I dare not disagree-as much as I’d like it otherwise.”

“Then I shall buy a few of these, in exchange for a Bill of Exchange, denominated in thalers, and payable at the House of the Golden Mercury in Leipzig,” said Eliza, indicating the Land Bank notes, “but I shall exchange them immediately for a lot of these.” She licked a finger and began to count off Bank of England notes.

“You place your trust in the Whigs? Roger shall be overjoyed.”

“I place my trust in Newton,” Eliza said.

“You refer to his new position at the Mint.”

“I had more in mind the calculus.”

“How so?”

“This is really a matter of derivatives, is it not?”

“Financial derivatives?”

“No, mathematical ones! For any quantity-say, position-there is a derivative, representing its rate of change. As I see it, England’s stock of land represents a fixed quantity of wealth. But commerce I see as a derivative-it is the slope, the speed, the rate of change of the nation’s wealth. When commerce stagnates, this rate of change is small, and money founded upon it is worthless. Hence the lopsided exchange rate you told me of. But when commerce thrives, all goes into rapid movement, the derivative jumps up, and money founded on it becomes of much greater value. Once Newton goes to work at the Mint, the supply of coin in England can only improve. Commerce, which has been frozen for lack of money, will surge, at least briefly. The exchange rate between these two currencies will swing the opposite way, long enough at least for me to take a profit.”

“It is a way of looking at the thing I had not considered before,” said Daniel, “and it sounds right to me. But if you ever have an opportunity to expound your theory to Isaac, I hope you’ll use the word fluxion in place of derivative.”

“What’s a fluxion?”

“That,” said Daniel, “is the problem in a nutshell.”

An Abandoned Church in France MARCH 1696

“I DO HOPE YOU’LL RECONSIDER, now, all of the unpleasant things you have had to say in the past about Satan.” This was how Anne-Marie de Crepy, duchesse d’Oyonnax, greeted her cousin when his eyelids-which had been closed, three days ago, by a Jesuit father in Versailles-twitched open.

Father Edouard de Gex looked up at a black sky, framed in the aperture of his coffin. It was an uncommonly plush model, for a Jesuit. The brothers of his order had loaded him at first into a Spartan pine-plank box. But Madame la duchesse and her entourage had appeared just in time, and put a stop to it. “Imitation of Christ is all well and good during life, but my cousin is in Heaven now, and nothing prevents me from treating his earthly remains with decent respect; besides, I must accompany him all the way home, and I’d have the casket well sealed.” And she had caused to be brought in to the sick-room a coffin so heavy it took four men to lift it: a coffin of oak, lined with lead, and cushioned better than most of the beds that courtiers slept on in Versailles. And so cunningly had it been wrought that even the pallbearers who carried it and its contents out to the street and set it on a flower-strewn gun-carriage would never have guessed that not only was it not sealed, but ventilation-slots ran all the way round the lip where the lid overhung the sides.