“You must have made a mistake,” said the Jew. “Which is perfectly all right-we all make mistakes. You reached into the wrong pocket and you pulled out your black money*-the stuff you throw to beggars.”

“Ahem, er, so I did,” Isaac said. “Pardon me-where’s the money for paying merchants?” Patting a few other pockets. “By the way, assuming I’m not going to offer you black money, how many shillings?”

“When you say shillings, I assume you mean the new ones?”

“The James I?”

“No, no, James I died half a century ago and so one would not normally use the adjective new to describe pounds minted during his reign.”

“Did you say pounds?” Daniel asked. “A pound is rather a lot of money, and so it strikes me as not relevant to this transaction, which has all the appearances of a shilling type of affair at most.”

“Let us use the word coins until I know whether you speak of the new or the old.”

“ Newmeaning the coins minted, say, during our lifetimes?”

“I mean the Restoration coinage,” the Israelite said, “or perhaps your professors have neglected to inform you that Cromwell is dead, and Interregnum coins demonetized these last three years.”

“Why, I believe I have heard that the King is beginning to mint new coins,” Isaac said, looking to Daniel for confirmation.

“My half-brother in London knows someone who saw a goldcarolus ii dei gratia coin once, displayed in a crystal case on a silken pillow,” Daniel said. “People have begun to call them Guineas, because they are made of gold that the Duke of York’s company is taking out of Africa.”

“I say, Daniel, is it true what they say, that those coins are perfectly circular?”

“They are, Isaac-not like the good old English hammered coins that you and I carry in such abundance in our pockets and purses.”

“Furthermore,” said the Ashkenazi, “the King brought with him a French savant, Monsieur Blondeau, on loan from King Louis, and that fellow built a machine that mills delicate ridges and inscriptions into the edges of the coins.”

“Typical French extravagance,” Isaac said.

“The King really did spend more time than was good for him in Paris,” Daniel said.

“On the contrary,” the forelocked one said, “if someone clips or files a bit of metal off the edge of a round coin with a milled edge, it is immediately obvious.”

“That must be why everyone is melting those new coins down as fast as they are minted, and shipping the metal to the Orient…?” Daniel began,

“… making it impossible for the likes of me and my friend to obtain them,” Isaac finished.

“Now there is a good idea-if you can show me coins of a bright silver color-not that black stuff-I’ll weigh them and accept them as bullion.”

“ Bullion!Sir!”

“Yes.”

“I have heard that this is the practice in China,” Isaac said sagely. “But here in England, a shilling is a shilling.”

“No matter how little it weighs!?”

“Yes. In principle, yes.”

“So when a lump of metal is coined in the Mint, it takes on a magical power of shillingness, and even after it has been filed and clipped and worn down to a mere featureless nodule, it is still worth a full shilling?”

“You exaggerate,” Daniel said. “I have here a fine Queen Elizabeth shilling, for example-which I carry around, mind you, as a souvenir of Gloriana’s reign, since it is far too fine a specimen to actually spend. But as you can see, it is just as bright and shiny as the day it was minted-”

“Especially where it’s recently been clipped there along the side,” the lens-grinder said.

“Normal, pleasing irregularity of the hand-hammered currency, nothing more.”

Isaac said, “My friend’s shilling, though magnificent, and arguably worth two or even three shillings in the market, is no anomaly. Here I have a shilling from the reign of Edward VI, which I obtained after an inebriated son of a Duke, who happened to have borrowed a shilling from me some time earlier, fell unconscious on a floor-the purse in which he carried his finest coins fell open and this rolled out of it-I construed this as repayment of the debt, and the exquisite condition of the coin as interest.”

“How could it roll when three of its edges are flat? It is nearly triangular,” the lens-grinder said.

“A trick of the light.”

“The problem with that Edward VI coinage is that for all I knew it might’ve been issued during the Great Debasement, when, before Sir Thomas Gresham could get matters in hand, prices doubled.”

“The inflation was not because the coins were debased, as some believe,” Daniel said, “it was because the wealth confiscated from the Papist monasteries, and cheap silver from the mines of New Spain, were flooding the country.”

“If you would allow me to approach within ten feet of these coins, it would help me to appreciate their numismatic excellence,” the lens-grinder said. “I could even use some of my magnifying-lenses to…”

“I’m afraid I would be offended,” Isaac said.

“You could inspect this one as closely as you wanted,” Daniel said, “and find no evidence of criminal tampering-I got it from a blind innkeeper who had suffered frostbite in the fingertips-had no idea what he was giving me.”

“Didn’t he think to bite down on it? Like so?” said the Judaic individual, taking the shilling and crushing it between his rear molars.

“What would he have learned by doing that, sir?”

“That whatever counterfeit-artist stamped it out, had used reasonably good metal-not above fifty percent lead.”

“We’ll choose to interpret that as a wry jest,” Daniel said, “the likes of which you could never direct against this shilling, which my half-brother found lying on the ground at the Battle of Naseby, not far from fragments of a Royalist captain who’d been blown to pieces by a bursting cannon-the dead man was, you see, a captain who’d once stood guard at the Tower of London where new coins are minted.”

The Jew repeated the biting ceremony, then scratched at the coin in case it was a brass clinker japanned with silver paint. “Worthless. But I owe a shilling to a certain vile man in London, a hater of Jews, and I would drive a shilling’s worth of satisfaction from slipping this slug of pig-iron into his hand.”

“Very well, then-” said Isaac, reaching for the prisms.

“Avid collectors such as you two must also have pennies-?”

“My father hands out shiny new ones as Christmas presents,” Daniel began. “Three years ago-” but he suspended the anecdote when he noticed that the lens-grinder was paying attention, not to him, but to a commotion behind them.

Daniel turned around and saw that it was a man, reasonably well-heeled, having trouble walking even though a friend and a servant were supporting him. He had a powerful desire to lie down, it seemed, which was most awkward, as he happened to be wading through ankle-deep mud. The servant slipped a hand between the man’s upper arm and his ribs to bear him up, but the man shrieked like a cat who’s been mangled under a cart-wheel and convulsed backwards and landed full-length on his back, hurling up a coffin-shaped wave of mud that spattered things yards away.

“Take your prisms,” said the merchant, practically stuffing them into Isaac’s pocket. He began folding up his display-case. If he felt the way Daniel did, then it wasn’t the sight of a man feeling ill, or falling down, that made him pack up and leave, so much as the sound of that scream.

Isaac was walking toward the sick man with the cautious but direct gait of a tightrope-walker.

“Shall we back to Cambridge, then?” Daniel suggested.

“I have some knowledge of the arts of the apothecary.” Isaac said, “Perhaps I could help him.”

A circle of people had gathered to observe the sick man, but it was a very broad circle, empty except for Isaac and Daniel. The victim appeared, now, to be trying to get his breeches off. But his arms were rigid, so he was trying to do it by writhing free of his clothes. His servant and his friend were tugging at the cuffs, but the breeches seemed to’ve shrunk onto his legs. Finally the friend drew his dagger, slashed through the cuffs left and right, and then ripped the pant-legs open from bottom to top-or perhaps the force of the swelling thighs burst them. They came off, anyway. Friend and servant backed away, affording Isaac and Daniel a clear vantage point that would have enabled them to see all the way up to the man’s groin, if the view hadn’t been blocked by black globes of taut flesh stacked like cannonballs up his inner thighs.