But the Emperor, kneeling with his nose to the glass, just behind which the bird twitched and convulsed, simply said: “This bird is dead and damned.” It died half a minute later, its yellow breast pointed upward at the fine ribbed vaults of the Great Hall, its head twisted weirdly to one side.

Margaretha’s headaches had not visited her in years, said Prince Heinrich, but a moment later she was apparently struck by one, for she mumbled, My head, and pitched forward headfirst onto the floor. And when, between the courtiers who gathered around Margaretha to attend to her, Ludmila and Katharina caught a glimpse of the gash on her head, and the blood that spurted from it, they gasped identically, went identically pale, and ran identically from the room.

“They were squeamish,” Prince Heinrich told the astronomer.

A disturbing hypothesis began to form in Heinrich’s head.

His nervousness returned. He stopped sleeping also.

He now undertook to observe Katharina and Ludmila—“with as much rigor, precision, and systematicity as you, Father, when I incarnate you as an astronomer rather than a confessor,” said Heinrich, “must observe the stars, the only difference being this, that when you observe the stars it is of no consequence whether or not the stars watch you in return, whereas in observing Katharina and Ludmila it was important that they not observe me observing them, at the risk of perverting what I observed of them.”

To that end he tried to move in darkness. Once again Prince Heinrich hung over his windows his tapestries.

At nightfall, instead of sleeping—“Impossible!”—and without, as yet, quite knowing why, Heinrich turned his attention to the putting together of air pumps, no longer the taking apart of clocks but now the putting together of air pumps, of bigger and bigger air pumps, the integrity of which he tested with more and more songbirds, as well as a few other animals. “I find it interesting, Father,” the Prince said, “how, over the course of centuries, we breed dogs to love us, we fashion dogs precisely such that they love us, with each new generation dogs love us, by design, more and more, a dog breed is not finished until it loves us, we do not really call it a dog at all until it loves us, before that point we call it a wolf—and yet when, after all that, a dog does, tautologically, love us, we are nevertheless moved.”