“Out for a stroll so soon, Doctor?”

Dappa’s evidently recognized him by the tread of his shoes and walking-stick on the quarterdeck-he hasn’t taken the spyglass away from his eye in half an hour.

“What about that schooner is so fascinating, Mr. Dappa? Other than that it’s full of murderers.”

“The Captain and I are having a dispute. I say it is a floaty and leewardly Flemish pirate-bottom. Van Hoek sees idioms in its rigging that argue to the contrary.”

“ Bottommeaning her hull- floatymeaning she bobs like a cork, with little below the water-line-which is desirable, I gad, for Flemings and pirates alike, as both must slip into shallow coves and harbors-”

“Perfect marks so far, Doctor.”

“ Leewardly,then, I suppose, means that because of that faintness in the keel, the wind tends to push her sideways through the water whenever she is sailing close-hauled-as she is now.”

“And as are we, Doctor.”

“ Minervahas the same defect, I suppose-”

This slander finally induces Dappa to take the spyglass away from his eye. “Why should you assume any such thing?”

“All these Amsterdam-ships are flat-bottomed of necessity, are they not? For entering the Ijsselmeer…”

“ Minervawas built on the Malabar coast.”

“Mr. Dappa!”

“I would not dishonor you with jests, Doctor. It is true. I was there.”

“But how-”

“ ’Tis an awkward time to be telling you the entire Narration,” Dappa observes. “Suffice it to say that she is not leewardly. Her apparent course is as close as it can be to her true course.”

“And you’d like to know, whether the same is true of yonder schooner,” Daniel says. “It is not unlike the problem an astronomer faces, when-imprisoned as he is on a whirling and hurtling planet-he tries to plot the true trajectory of a comet through the heavens.”

“Now it’s my turn to wonder whether you are jesting.”

“The water is like the C?lestial ?ther, a fluid medium through which all things move. Cape Cod, over yonder, is like the distant, fixed stars-by sighting that church-steeple in Provincetown, the High Land of Cape Cod to the south of it, the protruding mast of yonder wrack, and then by doing a bit of trigonometry, we may plot our position, and by joining one point to the next, draw our trajectory. The schooner, then, is like a comet-also moving through the ?ther-but by measuring the angles she makes with us and with the church-steeple, et cetera, we may find her true course; compare it with her apparent heading; and easily judge whether she is, or is not, leewardly.”

“How long would it take?”

“If you could make sightings, and leave me in peace to make calculations, I could have an answer in perhaps half an hour.”

“Then let us begin without delay,” Dappa says.

Plotting it out on the back of an old chart in the common room, Daniel begins to understand the urgency. To escape the confines of Cape Cod Bay, they must clear Race Point at the Cape’s northernmost tip. Race Point is northeast of them. The wind, for the last few hours, has been steady from northwest by north. Minerva can sail six points*from the wind, so she can just manage a northeasterly course. So leaving aside pirate-ships and other complications, she’s in a good position to clear Race Point within the hour.

But as a matter of fact there are two pirate-ships paralleling her course, much as the schooner-that-sucked and the ketch were doing earlier. To windward (i.e., roughly northwest of Minerva) is a big sloop-Teach’s flagship-which has complete freedom of movement under these circumstances. She’s fast, maneuverable, well-armed, capable of sailing four points from the wind, and well to the north of the dangerous shallows, hence in no danger of running aground off of Race Point. The schooner, on the other hand, is to leeward, between Minerva and the Cape. She can also sail four points from the wind-meaning that she should be able to angle across Minerva ’s course and grapple with her before Race Point. And if she does, there’s no doubt that Teach’s sloop will come in along the larboard side at the same moment, so that Minerva will be boarded from both sides at once. If that is all true, then Minerva ’s best course is to turn her stern into the wind, fall upon the schooner, attack, and then come about (preferably before running aground on the Cape) and contend with the sloop.

But if Dappa is right, and the schooner suffers from the defect of leewardliness, then all’s not as it seems. The wind will push her sideways, away from Minerva and toward the Race Point shallows-she won’t be able to intercept Minerva soon enough, and, to avoid running aground, she’ll have to tack back to the west, taking her out of the action. If that is true, Minerva ’s best course is to maintain her present close-hauled state and wait for Teach’s sloop to make a move.

It’s all in the arithmetic-the same sort of arithmetic that Flamsteed, the Astronomer Royal, is probably grinding through at this very moment at the Observatory in Greenwich, toiling through the night in hopes of proving that Sir Isaac’s latest calculation of the orbit of the moon is wrong. Except here Minerva ’s the Earth, that schooner is Luna, and fixed Boston is, of course, the Hub of the Universe. Daniel passes an extraordinarily pleasant half-hour turning Dappa’s steady observations into sines and cosines, conic sections and fluxions. Pleasant because it is imbued with the orderliness that taketh away his fear. Not to mention a fascination that makes him forget the throbbing and pulling stitches in his flesh.

“Dappa is correct. The schooner drifts to leeward, and will soon fall by the wayside or run aground,” he announces to van Hoek, up on the poop deck. Van Hoek puffs once, twice, thrice on his pipe, then nods and goes into Dutch mutterings. Mates and messenger-boys disseminate his will into all compartments of the ship. Minerva forgets about the schooner and bends all efforts to the expected fight against Teach’s wicked sloop-of-war.

In another half-hour, the leewardly schooner provides some coarse entertainment by actually running aground at the very knuckle of Cape Cod’s curled fist. This is ignominious, but hardly unheard-of; these English pirates have only been in Massachusetts for a couple of weeks and can’t expect to have all the sand-banks committed to memory. This skipper would rather run aground in soft sand, and refloat later, than flinch from battle and face Blackbeard Teach’s wrath.

Van Hoek immediately has them come about to west by south, as if they were going to sail back to Boston. His intent is to cut behind Teach’s stern and fire a broadside up the sloop’s arse and along her length. But Teach has too much intelligence for that, and so breaks the other way, turning to the east to get clear of Minerva ’s broadside, then wearing round to the south, pausing near the grounded schooner to pick up a few dozen men who might come in useful as boarders. After a short time he comes up astern of Minerva.

A tacking duel plays out there off of Race Point for an hour or so, Teach trying to find a way to get within musket-range of Minerva without being blown apart, van Hoek trying to fire just a single well-considered broadside. There are some paltry exchanges of fire. Teach puts a small hole in Minerva ’s hull that is soon patched, and a cloud of hurtling junk from one of Minerva ’s carronnades manages to carry away one of the sloop’s sails, which is soon replaced. But with time, even van Hoek’s hatred of pirates is worn down by the tedium, and by the need to get away from land while the sun is shining. Dappa reminds him that the Atlantic Ocean is just a mile or two that-a-way, and that nothing stands any more between them and it. He persuades van Hoek that there’s no better way to humiliate a pirate than to leave him empty-handed, his decks crowded with boarders who have nothing to throw their grappling-hooks at. To out-sail a pirate, he insists, is a sweeter revenge than to out-fight him.