Daniel went round the south side of the church even though it was not the most direct way, because he wanted to have a look at the south transept, which had collapsed some years ago. Rumor had it that the bigger and better stones were being carted away and used to build a new wing of John Comstock’s house on Piccadilly. Indeed, many of the stones had been removed to somewhere, but of course no one was working there now except for gravediggers.

Into Cheapside, where men on ladders were clambering into upper-story windows of a boarded-up house to remove limp, exhausted children who’d somehow outlived their families. Down in the direction of the river, the only gathering of people Daniel had seen: a long queue before the house of Dr. Nathaniel Hodges, one of the only physicians who hadn’t fled. Not far beyond that, on Cheapside, the house of John Wilkins himself. Wilkins had sent Daniel a key, which turned out not to be necessary, as his house had already been broken into. Floorboards pried up, mattresses gutted so that the place looked like a barn for all the loose straw and lumber on the floor. Whole ranks of books pawed from the shelves to see if anything was hidden behind. Daniel went round and re-shelved the books, holding back two or three newish ones that Wilkins had asked him to fetch.

Then to the Church of St. Lawrence Jewry.*“Follow the Drainpipes, find the Amphib’ns,” Wilkins had written. Daniel walked round the churchyard, which was studded with graves, but had not reached the graves-on-top-of-graves stage-Wilkins’s parishioners were mostly prosperous mercers who’d fled to their country houses. At one corner of the roof, a red copper vein descended from the downhill end of a rain-gutter, then ducked into a holed window beneath. Daniel entered the church and traced it down into a cellar where dormant God-gear was cached to expect the steady wheeling of the liturgical calendar (Easter and Christmas stuff, e.g.) or sudden reversals in the prevailing theology (High Church people like the late Bishop Laud wanted a fence round the altar so parish dogs couldn’t lift their legs on the Lord’s Table, Low Church primitives like Drake didn’t; the Rev. Wilkins, more in the Drake mold, had stashed the fence and rail down here). This room hummed, almost shuddered, as if a choir of monks were lurking in the corners intoning one of their chants, but it was actually the buzzing of a whole civilization of flies, so large that many of them seemed to be singing bass-these had grown from the corpses of rats, which carpeted the cellar floor like autumn leaves. It smelled that way, too.

The drain-pipe came into the cellar from a hole in the floor above, and emptied into a stone baptismal Font-a jumbo, total-baby-immersion style of Font-that had been shoved into a corner, probably around the time that King Henry VIII had kicked out the Papists. Daniel guessed as much from the carvings, which were so thick with symbols of Rome that to remove them all would have destroyed it structurally. When this vessel filled with rain-water from the drain-pipe it would spill excess onto the floor, and it would meander off into a corner and seep into the earth-perhaps this source of drinking-water had attracted the sick rats.

In any case the top of the font was covered with a grille held down by a couple of bricks-from underneath came contented croaking sounds. A gout of pink shot through an interstice and speared a fly out of midair, paused humming-taut for an instant, then snapped back. Daniel removed the bricks and pulled up the grille and looked at, and was looked at by, half a dozen of the healthiest frogs he’d ever seen, frogs the size of terriers, frogs that could tongue sparrows out of the air. Standing there in the City of Death, Daniel laughed. The generative spirit ran amok in the bodies of rats, whose corpses were transmuted into flies, which gave up their spirit to produce happy blinking green frogs.

Faint ticks, by the thousands, merged into a sound like wind-driven sleet against a windowpane. Daniel looked down to see it was just hordes of fleas who had abandoned the rat corpses and converged on him from all across the cellar, and were now ricocheting off his leather boots. He rummaged until he found a bread-basket, packed the frogs into it, imprisoned them loosely under a cloth, and walked out of there.

Though he could not see the river from here, he could infer that the tide was receding from the trickle of Thames-water that was beginning to probe its way down the gutter in the middle of Poultry Lane, running downhill from Leadenhall. Normally this would be a slurry of paper-scraps discarded by traders at the ‘Change, but today it was lumpy with corpses of rats and cats.

He gave that gutter as wide a berth as he could, but proceeded up against the direction of its flow to the edge of the goldsmiths’ district, whence Threadneedle and Poultry and Lombard and Cornhill sprayed confusingly. He continued up Cornhill to the highest point in the City of London, where Cornhill came together with Leadenhall (which carried on eastwards, but downhill from here) and Fish Street (downhill straight to London Bridge) and Bishopsgate (downhill towards the city wall, and Bedlam, and the plague-pit they’d dug next to it). In the middle of this intersection a stand-pipe sprouted, with one nozzle for each of those streets, and Thames-water rushed from each nozzle to flush the gutters. It was connected to a buried pipe that ran underneath Fish Street to the northern terminus of London Bridge. During Elizabeth’s time some clever Dutchmen had built water-wheels there. Even when the men who tended them were dead or run away to the country, these spun powerfully whenever the tide went out and high water accumulated on the upstream side of the bridge. They were connected to pumps that pressurized the Fish Street pipe and (if you lived on this hill) carried away the accumulated waste, or (if you lived elsewhere) brought a twice-daily onslaught of litter, turds, and dead animals.

He followed said onslaught down Bishopsgate, watching the water get dirtier as he went, but didn’t go as far as the wall-he stopped at the great house, or rather compound, that Sir Thomas (“Bad money drives out good”) Gresham had built, a hundred years ago, with money he’d made lending to the Crown and reforming the coinage. Like all old half-timbered fabricks it was slowly warping and bending out of true, but Daniel loved it because it was now Gresham’s College, home of the Royal Society.

And of Robert Hooke, the R.S.’s Curator of Experiments, who’d moved into it nine months ago-enabling him to do experiments all the time. Hooke had sent Daniel a list of odds and ends that he needed for his work at Epsom. Daniel deposited his frog-basket and other goods on the high table in the room where the Royal Society had its meetings and, using that as a sort of base-camp, made excursions into Hooke’s apartment and all of the rooms and attics and cellars that the Royal Society had taken over for storage.

He saw, and rummaged through, and clambered over, slices of numerous tree-trunks that someone had gathered in a bid to demonstrate that the thin parts of the rings tended to point towards true north. A Brazilian compass-fish that Boyle had suspended from a thread to see if (as legend had it) it would do the same (when Daniel came in, it was pointing south by southeast). Jars containing: powder of the lungs and livers of vipers (someone thought you could produce young vipers from it), something called Sympathetic Powder that supposedly healed wounds through a voodoo-like process. Samples of a mysterious red fluid taken from the Bloody Pond at Newington. Betel-nut, camphire-wood, nux vomica, rhino-horn. A ball of hair that Sir William Curtius had found in a cow’s belly. Some experiments in progress: a number of pebbles contained in glass jars full of water, the necks of the jars just barely large enough to let the pebbles in; later they would see if the pebbles could be removed, and if not, it would prove that they had grown in the water. Very large amounts of splintered lumber of all types, domestic and foreign-the residue of the Royal Society’s endless experiments on the breaking-strength of wooden beams. The Earl of Balcarres’s heart, which he had thoughtfully donated to them, but not until he had died of natural causes. A box of stones that various people had coughed up out of their lungs, which the R.S. was saving up to send as a present to the King. Hundreds of wasps’ and birds’ nests, methodically labeled with the names of the proud patrons who had brought them in. A box of baby vertebrae which had been removed from a large abscess in the side of a woman who’d had a failed pregnancy twelve years earlier. Stored in jars in spirits of wine: various human f?tuses, the head of a colt with a double eye in the center of its forehead, an eel from Japan. Tacked to the wall: the skin of a seven-legged, two-bodied, single-headed lamb. Decomposing in glass boxes: the Royal Society’s viper collection, all dead of starvation; some had their heads tied to their tails as part of some sort of Uroburos experiment. More hairballs. The heart of an executed person, superficially no different from that of the Earl of Balcarres. A vial containing seeds that had supposedly been voided in the urine of a maid in Holland. A jar of blue pigment made from tincture of galls, a jar of green made from Hungarian vitriol. A sketch of one of the Dwarves who supposedly inhabited the Canary Islands. Hundreds of lodestones of various sizes and shapes. A model of a giant crossbow that Hooke had designed for flinging harpoons at whales. A U-shaped glass tube that Boyle had filled with quicksilver to prove that its undulations were akin to those of a pendulum.