Pepys, Comstock, the Bishop of Chester, and Enoch the Red climbed out. Down in the tunnel, lights were now being lit. Consequently, through an open window, Daniel could see a banquet laid: a leg of mutton, a wheel of Cheshire, a dish of larks, ale, China oranges. But this room was not a dining-hall. In its corners he could see the gleam of retorts and quicksilver-flasks and fine balances, the glow of furnaces. He had heard rumors that the King had caused an alchemical laboratory to be built in the bowels of Whitehall, but until now, they had only been rumors.

“My coachman will take you back to Mr. Raleigh Waterhouse’s residence,” Pepys told him, pausing at the lip of the stairway. “Please make yourself comfortable below.”

“You are very kind, sir, but I’m not far from Raleigh’s, and I could benefit from the walk.”

“As you wish. Please give my compliments to Mr. Oldenburg when you see him.”

“I shall be honored to do so,” Daniel answered, and just restrained himself from saying, Please give mine to the King!

Daniel now worked up his courage and walked down into the Sermon Court and gazed up into the windows of the King’s chambers, though not for long-he was trying to look as if he came here all the time. A little side passage, under the end of the Privy Gallery, got him into the corner of the Privy Garden, which was a vast space. Another gallery ran along its edge, parallel to the river, and by going down it he could have got all the way to the royal bowling green and thence down into Westminster. But he’d had enough excitement for just now-instead he cut back across the great Garden, heading towards the Holbein Gate. Courtiers strolled and gossiped all round. Every so often he turned around and gazed back towards the river to admire the lodgings of the King and the Queen and their household rising up above the garden with the golden light of many beeswax candles shining out of them.

If Daniel had truly been the man about town that, for a few minutes, he was pretending to be, he’d have had eyes only for the people in the windows and on the garden paths. He’d have strained to glimpse something-a new trend in the cut of Persian vests, or two important Someones exchanging whispers in a shadowed corner. But as it was, there was one spectacle, and one only, that drew his gaze, like Polaris sucking on a lodestone. He turned his back on the King’s dwellings and looked south across the garden and the bowling green towards Westminster.

There, mounted up high on a weatherbeaten stick, was a sort of irregular knot of stuff, barely visible as a gray speck in the moonlight: the head of Oliver Cromwell. When the King had come back, ten years ago, he’d ordered the corpse to be dug up from where Drake and the others had buried it, and the head cut off and mounted on a pike and never taken down. Ever since then Cromwell had been looking down helplessly upon a scene of unbridled lewdness that was Whitehall Palace. And now Cromwell, who had once dandled Drake’s youngest son on his knee, was looking down upon him.

Daniel tilted his head back and looked up at the stars and supposed that seen from Drake’s perspective up in Heaven it must all look like Hell-and Daniel right in the middle of it.

BEING LOCKED UPin the Tower of London had changed Henry Oldenburg’s priorities all around. Daniel had expected that the Secretary of the Royal Society would jump headfirst into the great sack of foreign mail that Daniel had brought him, but all he cared about was the new lute-strings. He’d grown too fat to move around very effectively and so Daniel fetched necessaries from various parts of the half-moon-shaped room: Oldenburg’s lute, extra candles, a tuning-fork, some sheet-music, more wood on the fire. Oldenburg turned the lute over across his knees like a naughty boy for spanking, and tied a piece of gut or two around the instrument’s neck to serve as frets (the old ones being worn through), then replaced a couple of broken strings. Half an hour of tuning ensued (the new strings kept stretching) and then, finally, Oldenburg got what he really ached for: he and Daniel, sitting face to face in the middle of the room, sang a two-part song, the parts cleverly written so that their voices occasionally joined in chords that resonated sweetly: the curving wall of the cell acting like the mirror of Newton’s telescope to reflect the sound back to them. After a few verses, Daniel had his part memorized, and so when he sang the chorus he sat up straight and raised his chin and sang loudly at those walls, and read the graffiti cut into the stone by prisoners of centuries past. Not your vulgar Newgate Prison graffiti-most of it was in Latin, big and solemn as gravestones, and there were astrological diagrams and runic incantations graven by imprisoned sorcerers.

Then some ale to cool the wind-pipes, and a venison pie and a keg of oysters and some oranges contributed by the R.S., and Oldenburg did a quick sort of the mail-one pile containing the latest doings of the Hotel Montmor salon in Paris, a couple of letters from Huygens, a short manuscript from Spinoza, a large pile of ravings sent in by miscellaneous cranks, and a Leibniz-mound. “This damned German will never shut up!” Oldenburg grunted-which, since Oldenburg was himself a notoriously prolix German, was actually a jest at his own expense. “Let me see… Leibniz proposes to found a Societas Eruditorum that will gather in young Vagabonds and raise them up to be an army of Natural Philosophers to overawe the Jesuits… here are his thoughts on free will versus predestination… it would be great sport to get him in an argument with Spinoza… he asks me here whether I’m aware Comenius has died… says he’s ready to pick up the faltering torch of Pansophism*… here’s a light, easy-to-read analysis of how the bad Latin used by Continental scholars leads to faulty thinking, and in turn to religious schism, war, bad philosophy…”

“Sounds like Wilkins.”

“Wilkins! Yes! I’ve considered decorating these walls with some graffiti of my own, and writing it in the Universal Character… but it’s too depressing. ‘Look, we have invented a new Philosophickal Language so that when we are imprisoned by Kings we can scratch a higher form of graffiti on our cell walls.’ “

“Perhaps it’ll lead us to a world where Kings can’t, or won’t, imprison us at all-”

“Now you sound like Leibniz. Ah, here are some new mathematical proofs… nothing that hasn’t been proved already, by Englishmen… but Leibniz’s proofs are more elegant… here’s something he has modestly entitled Hypothesis Physica Nova. Good thing I’m in the Tower, or I’d never have time to read all this.”

Daniel made coffee over the fire-they drank it and smoked Virginia tobacco in clay-pipes. Then it was time for Oldenburg’s evening constitutional. He preceded Daniel down a stack of stone pie-wedges that formed a spiral stair. “I’d hold the door and say ‘after you,’ but suppose I fell-you’d end up in the basement of Broad Arrow Tower crushed beneath me-and I’d be in the pink.”

“Anything for the Royal Society,” Daniel jested, marveling at how Oldenburg’s bulk filled the helical tube of still air.

“Oh, you’re more valuable to them than I am,” Oldenburg said.

“Poh!”

“I am near the end of my usefulness. You are just beginning. They have great plans for you-”

“Until yesterday I wouldn’t’ve believed you-then I was allowed to hear a conversation-perfectly incomprehensible to me-but it sounded frightfully important.”

“Tell me about this conversation.”

They came out onto the top of the old stone curtain-wall that joined Broad Arrow Tower to Salt Tower on the south. Arm in arm, they strolled along the battlements. To the left they could look across the moat-an artificial oxbow-lake that communicated with the Thames-and a defensive glacis beyond that, then a few barracks and warehouses having to do with the Navy, and then the pasture-grounds of Wapping crooked in an elbow of the Thames, dim lights out at Ratcliff and Limehouse-then a blackness containing, among other things, Europe.