Leibniz unlatched the double doors, turned around, and backed through them so that he could watch her face. He saw light reflected in her blue eyes: light from high windows all around the room, and from sparking fireworks set in buckets of sand to make it look like one great birthday-cake.
The library had been built two stories high, with a catwalk all around, halfway up, to afford access to the higher shelves, and its walls and the frescoed vault overhead had been generously arched with windows so that “Aunt Figgy” (short for Figuelotte, as Queen Sophie Charlotte was known to her family) and her bookish friends could read into the evening without need of candles. The high windows had been cracked open to let the room breathe in warm summer air and to exhale the smoke from the fizzing sparklers. The frescoes depicted the same assortment of Classical scenes that covered the ceiling of every rich person in Christendom nowadays, though the gods and goddesses had been provided with blond hair and blue eyes so that Jupiter might as well have been Wotan. Trompe l’oeil made it look as if the library had no ceiling but was open to the blue skies, and the gods were all springing out of frothy clouds. The writhing columns of smoke from the fireworks spread out against the plaster-work and swirled about to make the illusion that much better.
A cheer and a little song followed, from the dozen or so people who had come to wish Caroline Glück on her Geburtstag. It was a small party, for a Princess, and it was an older crowd. Sophie was the eldest of all at seventy-one—she had come out from Hanover, crammed into a carriage with Leibniz and her grandchildren: George August (who was a few months younger than Caroline) and Sophie Dorothea (four years younger yet). Sophie Charlotte (Figuelotte), Queen of Prussia and the mistress and namesake of the palace, was here with her son Frederick William, a legendary brat of thirteen. Filling out the guest list was the motliest collection of metaphysicians, mathematicians, radical theologians, writers, musicians, and poets ever brought together for a princess’s eighteenth birthday.
The Queen of Prussia liked to stage operas, when she wasn’t inciting riotous dinner-table debates among her friends, and the only sense in which she was ever a tyrant was in ordering some poor physicist to don a mad-cap and warble a role for which he was untrained and ill-suited. Princess Caroline had been dragooned, from time to time, to sing a Nymph or Angel part. Nothing, except perhaps for fighting side-by-side in a war, forged bonds among disparate persons so well as performing together on stage, and so Caroline had become a great friend of these grownups, her fellow-sufferers on the boards of the Charlottenburg.
With wine-glasses and sparklers in hand they had gathered round a pedestal that had been built of polished cherry-wood in the center of the library. Surmounting this, and spreading out above the heads of the revelers, was a large spherical object—
“A cage!” Caroline exclaimed.
Dismay flowed over Leibniz’s face. But very soon that emotion gave way to a sort of distracted, intrigued look, as his curiosity had been somehow provoked. He bobbed his head in a way that might have been a nod, or a bow. “C’est juste,” he said. “Geometers have, with their parallels and meridians, ruled the globe that, being unmarked, save by irregular coastlines and river-courses, seemed wild to eyes that only in order could see beauty. But one who loves Nature for her variety might see the geometers’ devices as a disfigurement—no bird is as beautiful when seen through the bars of a cage, as it is in the wild. But I pray, Highness, that you will construe this rather as an inventory of the known. It is a map of the world, not as flattened out by cartographers, but as it is.”
The globe had been set at an angle, as the earth was tilted with respect to the ecliptic. An unexplored portion of the South Pacific bore on the pedestal. Not far away from it, the south pole presented itself just at the level of Caroline’s head. This globe was indeed fashioned like a spherical bird-cage, with curving brass bars following the lines of longitude and latitude. Most of it (the oceans) was open-work. But the continents were curved plates of brass riveted to those bars. They were mounted to the inside of the cage, rather than the outside, so that the bars passed in front of them—at least, for the celebrants who were standing around it. An irregular, wholly factitious continent had been placed around the south pole, representing the hypothetical land of Antarctica, and this had a round hatchway cut into it, and steps leading up to it from the floor.