“I need you to draw a reticule on a leaf of paper and then hold it up at various measured distances from my cornea-as you do, I’ll move the darning needle up and down-creating greater and lesser distortions in the shape of my eyeball-I say, I’ll do that with one hand, and take notes of what I see with the other.”
So the night proceeded-by sunrise, Isaac Newton knew more about the human eye than anyone who had ever lived, and Daniel knew more than anyone save Isaac. The experiment could have been performed by anyone. Only one person had actually done it, however. Newton pulled the needle out of his eye, which was blood-red, and swollen nearly shut. He turned to another part of the Waste Book and began wrestling with some difficult math out of Cartesian analysis while Daniel stumbled downstairs and went to church. The sun turned the stained-glass windows of the chapel into matrices of burning jewels.
Daniel saw in a way he’d never seen anything before: his mind was a homunculus squatting in the middle of his skull, peering out through good but imperfect telescopes and listening-horns, gathering observations that had been distorted along the way, as a lens put chromatic aberrations into all the light that passed through it. A man who peered out at the world through a telescope would assume that the aberration was real, that the stars actually looked like that-what false assumptions, then, had natural philosophers been making about the evidence of their senses, until last night? Sitting in the gaudy radiance of those windows hearing the organ play and the choir sing, his mind pleasantly intoxicated from exhaustion, Daniel experienced a faint echo of what it must be like, all the time, to be Isaac Newton: a permanent ongoing epiphany, an endless immersion in lurid radiance, a drowning in light, a ringing of cosmic harmonies in the ears.
DANIEL BECOMES AWAREthat someone is standing over him as he lies on the deck: a stubby red-headed and -bearded man with a lit cigar in his mouth, and spectacles with tiny circular lenses: it’s van Hoek, the captain, just checking to see whether his passenger will have to be buried at sea tomorrow. Daniel sits up, finally, and introduces himself, and van Hoek says very little-probably pretending to know less English than he really does, so Daniel won’t be coming to his cabin and pestering him at all hours. He leads Daniel aft along Minerva ’s main deck (which is called the upperdeck, even though, at the ends of the ship, there other other decks above it) and up a staircase to the quarter-deck and shows him to a cabin. Even van Hoek, who can be mistaken for a stout ten-year-old if you see him from behind, has to crouch to avoid banging his head on the subtly arched joists that support the poop deck overhead. He raises one arm above his head and steadies himself against a low beam-touching it not with a hand, but a brass hook.
Even though small and low-ceilinged, the cabin is perfectly all right-a chest, a lantern, and a bed consisting of a wooden box containing a canvas sack stuffed with straw. The straw is fresh, and its aroma will continue to remind Daniel of the green fields of Massachusetts all the way to England. Daniel strips off just a few items of clothing, curls up, and sleeps.
When he wakes up, the sun is in his eyes. The cabin has a small window (its forward bulkhead is deeply sheltered under the poop deck and so it is safe to put panes of glass there). And since they are sailing eastwards, the rising sun shines into it directly-along the way, it happens to beam directly through the huge spoked wheel by which the ship is steered. This is situated just beneath the edge of that same poop deck so that the steersman can take shelter from the weather while enjoying a clear view forward down almost the entire length of Minerva. At the moment, loops of rope have been cast over a couple of the handles at the ends of the wheel’s spokes and tied down to keep the rudder fixed in one position. No one is at the wheel, and it’s neatly dividing the red disk of the rising sun into sectors.
IN THE GREAT COURTof Trinity there was a sundial Isaac Newton didn’t like: a flat disk divided by labeled spokes with a gnomon angling up from the center, naively copied from Roman designs, having a certain Classical elegance, and always wrong. Newton was constructing a sundial on a south-facing wall, using, as gnomon, a slender rod with a ball on the end. Every sunny day the ball’s shadow would trace a curve across the wall-a slightly different curve every day, because the tilt of the earth’s axis slowly changed through the seasons. That sheaf of curves made a fine set of astronomical data but not a usable timepiece. To tell time, Isaac (or his faithful assistant, Daniel Waterhouse) had to make a little cross-tick at the place the gnomon’s shadow stood when Trinity’s bell (always just a bit out of synchronization with King’s) rang each of the day’s hours. In theory, after 365 repetitions of this daily routine, each of the curves would be marked with ticks for 8:00a.m., 9:00a.m., and so on. By connecting those ticks-drawing a curve that passed through all of the eight o’clock ticks, another through all of the nine o’clock ticks, and so on-Isaac produced a second family of curves, roughly parallel to one another and roughly perpendicular to the day curves.
One evening, about two hundred days and over a thousand cross-ticks into this procedure, Daniel asked Isaac why he found sundials so interesting. Isaac got up, fled the room, and ran off in the direction of the Backs. Daniel let him be for a couple of hours and then went out looking for him. Eventually, at about two o’clock in the morning, he found Isaac standing in the middle of Jesus Green, contemplating his own long shadow in the light of a full moon.
“It was a sincere request for information-nothing more-I want you to convey to me whatever it is about sundials I’ve been too thick-headed to find very interesting.”
This seemed to calm Isaac down, though he did not apologize for having thought the worst about Daniel. He said something along the lines of: “Heavenly radiance fills the ?ther, its rays parallel and straight and, so long as nothing is there to interrupt them, invisible. The secrets of God’s creation are all told by those rays, but told in a language we do not understand, or even hear-the direction from which they shine, the spectrum of colors concealed within the light, these are all characters in a cryptogram. The gnomon-look at our shadows on the Green! We are the gnomon. We interrupt that light and we are warmed and illuminated by it. By stopping the light, we destroy part of the message without understanding it. We cast a shadow, a hole in the light, a ray of darkness that is shaped like ourselves-some might say that it contains no information save the profile of our own forms-but they are wrong. By recording the stretching and skewing of our shadows, we can attain part of the knowledge hidden in the cryptogram. All we need to make the necessary observations is a fixed regular surface-a plane-against which to cast the shadow. Descartes gave us the plane.”
And so from then onwards Daniel understood that the point of this grueling sundial project was not merely to plot the curves, but to understand why each curve was shaped as it was. To put it another way, Isaac wanted to be able to walk up to a blank wall on a cloudy day, stab a gnomon into it, and draw all of the curves simply by knowing where the shadow would pass. This was the same thing as knowing where the sun would be in the sky, and that was the same as knowing where the earth was in its circuit around the sun, and in its daily rotation.
Though, as months went on, Daniel understood that Isaac wanted to be able to do the same thing even if the blank wall happened to be situated on, say, the moon that Christian Huygens had lately discovered revolving around Saturn.
Exactly how this might be accomplished was a question with ramifications that extended into such fields as: Would Isaac (and Daniel, for that matter) be thrown out of Trinity College? Were the Earth, and all the works of Man, nearing the end of a long relentless decay that had begun with the expulsion from Eden and that would very soon culminate in the Apocalypse? Or might things actually be getting better, with the promise of continuing to do so? Did people have souls? Did they have Free Will?